Rev Drops, Almost Stalling

[albi969]

Hello All

Just a quickie for any mechanics etc out there.

What would be the obvious (and not so obvious) signs of a faulty throttle position sensor.

I have a 98 Corolla 1.6 lift back (4afe engine & 43000 miles)and been having erratic idle problems , sudden rev drops ,almost stalling all since cam belt change at Toyota, been back with it and they renewed spark plugs ( due to diagnostic report ).Matters have improved slightly but not cured. Car ran spot on before belt change .

Thanks in advance for any insight offered.

Cheers

Albi java script:emoticon('', 'smid_18')

[Twincam.GTi]

I have a 98 Corolla 1.6 lift back (4afe engine & 43000 miles)and been having erratic idle problems , sudden rev drops ,almost stalling

I'm coming it at this from a totally different 'angle' but are your rev's 'fluttering' between around 600 to 1000 r.p.m approx.?

Also when was your car last submitted for M.O.T? ...and more importantly what was the emission part like?

Reason I ask this is I've recently had a 1998 Corolla 1.6 GS 3dr fail the M.O.T on the emission test only (due to all 'cat' equiped cars having to do a 'stricter test' ...1st idle test, 2nd idle test etc. etc.); it was running 'rich'.

The car in question also suffered from (what sounds to be) the same erratic tick over as yours.

The fault ...

...Oxygen sensor (sometimes refered to as a Lambda Sensors ...the name comes from the person who invented it ...I think !?) was faulty and needed replacement.

As a side note although the test showed car was running 'rich' NO Diagnostic codes 'showed up'

To quote from an article:

"Replacing Oxygen / Lambda Sensors

Everybody knows that spark plugs have to be replaced periodically to maintain peak engine performance, but many people don't realise the same goes for oxygen sensors. As long the lambda sensor is working properly, there's no reason to replace it. But after 30,000 to 50,000 miles of being constantly bathed in hot exhaust gas, a build up of deposits on the sensor tip can make it sluggish. If there's enough clinker on the sensor tip, the sensor may produce little or no voltage at all. This produces a false "lean" signal that makes the computer think the engine needs more fuel, which it doesn't but gets anyway. This creates a rich fuel condition that kills fuel economy and sends carbon monoxide and hydrocarbon emissions soaring. The engine may also experience additional drivability problems such as surging or hesitation."

And regards to engine codes:

"If you don't find any codes, that doesn't necessarily mean the lambda sensor is okay. In many instances, a sluggish sensor may not be bad enough to record a fault code but will still be causing an emissions or drivability problem."

After replacement of the sensor all is well, perfect idling and a 'PASS'.

I say "all is well', but the price of a genuine Toyota sensor is around £100 (whereas Ford and Vauxhall ones are about £30 - £40).

I'm not saying this is YOUR problem but it may be another avenue to take / ask about at your garage.

I also realise you want to be sure before spending £100 or so quid.

[albi969]

I have a 98 Corolla 1.6 lift back (4afe engine & 43000 miles)and been having erratic idle problems , sudden rev drops ,almost stalling

I'm coming it at this from a totally different 'angle' but are your rev's 'fluttering' between around 600 to 1000 r.p.m approx.?

Also when was your car last submitted for M.O.T? ...and more importantly what was the emission part like?

Reason I ask this is I've recently had a 1998 Corolla 1.6 GS 3dr fail the M.O.T on the emission test only (due to all 'cat' equiped cars having to do a 'stricter test' ...1st idle test, 2nd idle test etc. etc.); it was running 'rich'.

The car in question also suffered from (what sounds to be) the same erratic tick over as yours.

The fault ...

...Oxygen sensor (sometimes refered to as a Lambda Sensors ...the name comes from the person who invented it ...I think !?) was faulty and needed replacement.

As a side note although the test showed car was running 'rich' NO Diagnostic codes 'showed up'

To quote from an article:

"Replacing Oxygen / Lambda Sensors

Everybody knows that spark plugs have to be replaced periodically to maintain peak engine performance, but many people don't realise the same goes for oxygen sensors. As long the lambda sensor is working properly, there's no reason to replace it. But after 30,000 to 50,000 miles of being constantly bathed in hot exhaust gas, a build up of deposits on the sensor tip can make it sluggish. If there's enough clinker on the sensor tip, the sensor may produce little or no voltage at all. This produces a false "lean" signal that makes the computer think the engine needs more fuel, which it doesn't but gets anyway. This creates a rich fuel condition that kills fuel economy and sends carbon monoxide and hydrocarbon emissions soaring. The engine may also experience additional drivability problems such as surging or hesitation."

And regards to engine codes:

"If you don't find any codes, that doesn't necessarily mean the lambda sensor is okay. In many instances, a sluggish sensor may not be bad enough to record a fault code but will still be causing an emissions or drivability problem."

After replacement of the sensor all is well, perfect idling and a 'PASS'.

I say "all is well', but the price of a genuine Toyota sensor is around £100 (whereas Ford and Vauxhall ones are about £30 - £40).

I'm not saying this is YOUR problem but it may be another avenue to take / ask about at your garage.

I also realise you want to be sure before spending £100 or so quid.

Thanks for the reply Twincam,

The car also seems to be suffering from periodic surging whilst driving( no movement of foot on accel pedal but car seems to speed up a little ) very slight but perceptible. The m.o.t was carried out at the same time as the belt change around a month ago, passed on emmisions.

The revs seem to vary at idle between 5-700 rpm repeatedly no aircon on or other accesories switched on.

How was the faulty lambda diagnosed on your car ?

As you say something else to look into.

Cheers

Albi.

[hoho15]

my car idles about 600 rpm normally

[kingdeacon]

has the collant been changed? or is it full? a air lock or low collant level can cause bad idol, as it did in mine when had a slight leaking hose

[Twincam.GTi]

albi969

Thanks for the reply Twincam,

The car also seems to be suffering from periodic surging whilst driving( no movement of foot on accel pedal but car seems to speed up a little ) very slight but perceptible. The m.o.t was carried out at the same time as the belt change around a month ago, passed on emmisions.

The revs seem to vary at idle between 5-700 rpm repeatedly no aircon on or other accesories switched on.

How was the faulty lambda diagnosed on your car ?

As you say something else to look into.

Cheers

Albi.

Yes there was also periodic but slight surging whislt driving at low speed (between 20m.p.h and 30 m.p.h).

The reason that I diagnosed a faulty lambda sensor was because of these driving problems (revs up and down when waitiing at traffic lights etc.) and the failure at emissions test part of M.O.T.

The lambda sensor was the first port of call (had already serviced car, new plugs and air filter etc.), if that had not worked in my case it may have been another 'cat'; so I was just (very) lucky!

However you state that your car did pass okay though and this is what does confuse me now about whether my original thoughts of it being definitely your Oxygen/Lamba sensor playing up. damn!

I note you also say that your cambelt was changed and at first I woundered if they may have 'slipped a tooth' when fitting but ... ...if that was the case car would be running extremely bad and I personally can't believe that a Toyota mechanic would let that happen anyway.

More questions:

What 'code'/diagnosis was brought up when you took it back?

...and what was there decision (other than just spark plug replacement)?

Also do you have a standard airbox/filter?

Finally what made you think TPS (has this been disturbed on your car?)?

Sorry for the questions but just trying to build up more of a picture to ascertain fault

[albi969]

has the collant been changed? or is it full? a air lock or low collant level can cause bad idol, as it did in mine when had a slight leaking hose

Thanks for the reply Kingdeacon,

The coolant level is as normal , although not mechanically minded i am a bit of an anorak when it comes to checking oil and fluids etc. I get some strange looks at work when i continually dive under the front of the car when i've just arrived or am about to leave. :)

[tea sport]

If this fault has only been present since the cam belt was changed it sounds to me like the belt has been fitted a tooth out. One tooth out can cause running problems. I have experienced a celica with the belt a tooth out, when the engine was cold it did'nt make much differance but only when it was warm a loss of power and poor idling.

[albi969]

albi969

Thanks for the reply Twincam,

The car also seems to be suffering from periodic surging whilst driving( no movement of foot on accel pedal but car seems to speed up a little ) very slight but perceptible. The m.o.t was carried out at the same time as the belt change around a month ago, passed on emmisions.

The revs seem to vary at idle between 5-700 rpm repeatedly no aircon on or other accesories switched on.

How was the faulty lambda diagnosed on your car ?

As you say something else to look into.

Cheers

Albi.

Yes there was also periodic but slight surging whislt driving at low speed (between 20m.p.h and 30 m.p.h).

The reason that I diagnosed a faulty lambda sensor was because of these driving problems (revs up and down when waitiing at traffic lights etc.) and the failure at emissions test part of M.O.T.

The lambda sensor was the first port of call (had already serviced car, new plugs and air filter etc.), if that had not worked in my case it may have been another 'cat'; so I was just (very) lucky!

However you state that your car did pass okay though and this is what does confuse me now about whether my original thoughts of it being definitely your Oxygen/Lamba sensor playing up. damn!

I note you also say that your cambelt was changed and at first I woundered if they may have 'slipped a tooth' when fitting but ... ...if that was the case car would be running extremely bad and I personally can't believe that a Toyota mechanic would let that happen anyway.

More questions:

What 'code'/diagnosis was brought up when you took it back?

...and what was there decision (other than just spark plug replacement)?

Also do you have a standard airbox/filter?

Finally what made you think TPS (has this been disturbed on your car?)?

,

I

Sorry for the questions but just trying to build up more of a picture to ascertain fault

Twincam ,

thanks once again for your info , believe me i have no problem with a few questions the more info i can provide gives people a better picture of the problem. :) .

The car is absolutey standard in every way airbox included.

When i took car back to Toyota after belt change, the service chap said that they would put the problems right if in the very unlikely event there had been some mistake on their part. Fair enough i thought.

A couple of hours later i get a call from them saying that their diagnostic eqpt had shown a faulty spark plug problem, they gave me the option of doing it myself , but as i was driving round Sheffield and wouldnt be back while late i asked them to do it. I didnt really fancy breaking down and waiting 2 hours for breakdown assistance.

They didnt give me the specific codes as i wasn't present at their premises- only on the end of a phone .The chap just told me the problem was sorted. Although this has since proved not to be the case :(

As for TPS symptons query, i was going on the assumption that as the problem seems to mainly manifest itself with acceleration ( hesitation etc and feeling of engine surge and kick when lifting foot off pedal plus kagarooing ) there may be some electronic wizardy failing to control this event. Iam going to ask them to sit in the car for maybe 2 or 3 mins after they drive the car so they can experience the erratic idle problem as i'm definately not imagining it

Hope this makes sense.

Anyway car is booked in for tommorow for another look.

Cheers Albi

[Twincam.GTi]

Having read all the above it does make me wonder (as others have said on this thread) if it IS a missed tooth on the Cambelt/one tooth out when belt changed; although I would like to stress it's not the sort of mistake I would expect from a Toyota Technician

However why did the Toyota dealer 'discover' a code fault?

Also did the mechanic desturb something when changing the belt, e.g. when lifting the rocker cover off (yes, rocker cover is also part of cambelt cover and lot needs to be removed) did a wire/ conection around the injection system nearby get desturbed? ...although again I would have thought Toyota dealer would have discovered/checked this when your car went back the second time.

When you take it back and have it sorted I'm sure alot of us on here will be interested to hear what it is (I certainly do!).

[albi969]

Having read all the above it does make me wonder (as others have said on this thread) if it IS a missed tooth on the Cambelt/one tooth out when belt changed; although I would like to stress it's not the sort of mistake I would expect from a Toyota Technician

However why did the Toyota dealer 'discover' a code fault?

Also did the mechanic desturb something when changing the belt, e.g. when lifting the rocker cover off (yes, rocker cover is also part of cambelt cover and lot needs to be removed) did a wire/ conection around the injection system nearby get desturbed? ...although again I would have thought Toyota dealer would have discovered/checked this when your car went back the second time.

When you take it back and have it sorted I'm sure alot of us on here will be interested to hear what it is (I certainly do!).

Hello All,

Well my friends the mystery continues as to why my 98 Corolla is not running right since Toyota changed the cam-belt.

Well you know the story so far , so won’t bore you with the details again.

Upshot is had the car back in to Toyota for 3 days and it has them stumped as to the continuing problems with the erratic idle.

Thursday took back and managed to speak to technician, explained the symptoms to him.

Said technician test drove the car and confirmed that he too experienced the problems regarding jumping idle when warmed up and jerkiness and kangarooing when backing off accelerator, he also said that he couldn’t really detect any surging at a constant speed. Thursday around 1700 hrs get a call back telling me that they have once again had the covers off etc and checked the belt and also had a timing light on it , everything checked out as it should.

Next step was another diagnostic check, no fault codes showing. This check was followed by a check with their “database” , showing what all sensors were doing. This check apparently showed that the oxygen sensor was not switching as it should.

The cost of new sensor would be £119 plus labour. Another possible cause may be a fault in wiring from Ecu to the sensor, could confirm this by wiring check at a further £76 , although this may save me shelling out for the sensor and then finding out it wasn’t needed. Anyway went with this idea .

I took the car in Friday and left with them to do the further wiring test. I get a call telling me that the wiring test confirms oxygen sensor is at fault and they have ordered new one for fitting today ( Saturday ) , anyway just had a call to tell me that fitting the new sensor has made no difference , so old one put back on and they have tried various other parts from another car to see if they make any difference, still no good news, now car is apparently running rich on emissions test.

So now am going to collect car and have another think….. Plus point if there is one is that I’m not going to be relieved of any money for the time they have had the car.

Any ideas ?

Regards

Albi

[215 compressor]

Having read all the above it does make me wonder (as others have said on this thread) if it IS a missed tooth on the Cambelt/one tooth out when belt changed; although I would like to stress it's not the sort of mistake I would expect from a Toyota Technician

However why did the Toyota dealer 'discover' a code fault?

Also did the mechanic desturb something when changing the belt, e.g. when lifting the rocker cover off (yes, rocker cover is also part of cambelt cover and lot needs to be removed) did a wire/ conection around the injection system nearby get desturbed? ...although again I would have thought Toyota dealer would have discovered/checked this when your car went back the second time.

When you take it back and have it sorted I'm sure alot of us on here will be interested to hear what it is (I certainly do!).

Hello All,

Well my friends the mystery continues as to why my 98 Corolla is not running right since Toyota changed the cam-belt.

Well you know the story so far , so won’t bore you with the details again.

Upshot is had the car back in to Toyota for 3 days and it has them stumped as to the continuing problems with the erratic idle.

Thursday took back and managed to speak to technician, explained the symptoms to him.

Said technician test drove the car and confirmed that he too experienced the problems regarding jumping idle when warmed up and jerkiness and kangarooing when backing off accelerator, he also said that he couldn’t really detect any surging at a constant speed. Thursday around 1700 hrs get a call back telling me that they have once again had the covers off etc and checked the belt and also had a timing light on it , everything checked out as it should.

Next step was another diagnostic check, no fault codes showing. This check was followed by a check with their “database” , showing what all sensors were doing. This check apparently showed that the oxygen sensor was not switching as it should.

The cost of new sensor would be £119 plus labour. Another possible cause may be a fault in wiring from Ecu to the sensor, could confirm this by wiring check at a further £76 , although this may save me shelling out for the sensor and then finding out it wasn’t needed. Anyway went with this idea .

I took the car in Friday and left with them to do the further wiring test. I get a call telling me that the wiring test confirms oxygen sensor is at fault and they have ordered new one for fitting today ( Saturday ) , anyway just had a call to tell me that fitting the new sensor has made no difference , so old one put back on and they have tried various other parts from another car to see if they make any difference, still no good news, now car is apparently running rich on emissions test.

So now am going to collect car and have another think….. Plus point if there is one is that I’m not going to be relieved of any money for the time they have had the car.

Any ideas ?

Regards

Albi

hi i work in the motor trade and it annoys me to hear that you have payed for a job doing and since have this problem it is there responsibilty to find out the cause has it has only occured since they worked on it last .surely something has been disturbed while changing the cambelt as said previously cam box has to be lifted to gain access, so plugs also are removed any damage to plug leads, are earth leads all fitted back on and vacuum pipes correctly .if i had fitted a cam belt and this had occured i would do my upmost to find the cause whether or not it was my fault.take it back to the garage it didnt do it before belt fitted :Ps still have doubts if belt out a tooth

[Twincam.GTi]

I realise I may be repeating myself here, but the faults you incured did seem to point to the Oxygen Sensor, and I am glad they did try changing it ..but then they said no change, fair enough, but ... did they actually take the car out for a RUN with the new oxygen sensor fitted (and not just sat on the ramp idling )?

INFO Picture: Oxygen/lambda Sensor fitted into front section of exhaust on 1998 Corolla 1.6

Also how come the emissions were fine with old Oxygen Sensor, then replace with new sensor, then put old sensor back in and emissions are high? ...this I feel makes no sense. Were they SURE the emissions were within limits the first time?

With regards to the Cambelt change, thankfully this member is thinking along the same lines, as I too wonder more and more if something was wrongly disturbed (even though done by Toyota Mechanic)...

215 compressor

hi i work in the motor trade and it annoys me to hear that you have payed for a job doing and since have this problem it is there responsibilty to find out the cause has it has only occured since they worked on it last .surely something has been disturbed while changing the cambelt as said previously cam box has to be lifted to gain access, so plugs also are removed any damage to plug leads, are earth leads all fitted back on and vacuum pipes correctly .if i had fitted a cam belt and this had occured i would do my upmost to find the cause whether or not it was my fault.take it back to the garage it didnt do it before belt fitted . :ffs:ps still have doubts if belt out a tooth

...when the cam box was removed.

Finally (and I don't really know how you can enforce this?) I would recomend that it is the SAME mechanic that works on/carries out the diagnosis/checks on your car.

Please keep informed, it's something that could affect us all!

[albi969]

I realise I may be repeating myself here, but the faults you incured did seem to point to the Oxygen Sensor, and I am glad they did try changing it ..but then they said no change, fair enough, but ... did they actually take the car out for a RUN with the new oxygen sensor fitted (and not just sat on the ramp idling )?

INFO Picture: Oxygen/lambda Sensor fitted into front section of exhaust on 1998 Corolla 1.6

Also how come the emissions were fine with old Oxygen Sensor, then replace with new sensor, then put old sensor back in and emissions are high? ...this I feel makes no sense. Were they SURE the emissions were within limits the first time?

With regards to the Cambelt change, thankfully this member is thinking along the same lines, as I too wonder more and more if something was wrongly disturbed (even though done by Toyota Mechanic)...

215 compressor

hi i work in the motor trade and it annoys me to hear that you have payed for a job doing and since have this problem it is there responsibilty to find out the cause has it has only occured since they worked on it last .surely something has been disturbed while changing the cambelt as said previously cam box has to be lifted to gain access, so plugs also are removed any damage to plug leads, are earth leads all fitted back on and vacuum pipes correctly .if i had fitted a cam belt and this had occured i would do my upmost to find the cause whether or not it was my fault.take it back to the garage it didnt do it before belt fitted . :ffs:ps still have doubts if belt out a tooth

...when the cam box was removed.

Finally (and I don't really know how you can enforce this?) I would recomend that it is the SAME mechanic that works on/carries out the diagnosis/checks on your car.

Please keep informed, it's something that could affect us all!

Hello All,

Firstly i feel i must apologise for the delay in replying to the latest suggestions, i 've been away for the last week and just got back today 19th.The corolla has been sat in my garage all last week, and took the other halfs battered but reliable Nexia to the coast.

Anyways, i will be taking the car back to Toyota this week and trying to solve the mystery as to my rough running motor, this will be the 3rd time its been in since belt change.

On the mechanic point , it would seem that the same mechanic seems to have carried out all work on the car since i've been taking it to them according to invoices etc so theres a plus point.

Will keep you all informed as to what happens.

Regards

Albi

[albi969]

I realise I may be repeating myself here, but the faults you incured did seem to point to the Oxygen Sensor, and I am glad they did try changing it ..but then they said no change, fair enough, but ... did they actually take the car out for a RUN with the new oxygen sensor fitted (and not just sat on the ramp idling )?

INFO Picture: Oxygen/lambda Sensor fitted into front section of exhaust on 1998 Corolla 1.6

Also how come the emissions were fine with old Oxygen Sensor, then replace with new sensor, then put old sensor back in and emissions are high? ...this I feel makes no sense. Were they SURE the emissions were within limits the first time?

With regards to the Cambelt change, thankfully this member is thinking along the same lines, as I too wonder more and more if something was wrongly disturbed (even though done by Toyota Mechanic)...

215 compressor

hi i work in the motor trade and it annoys me to hear that you have payed for a job doing and since have this problem it is there responsibilty to find out the cause has it has only occured since they worked on it last .surely something has been disturbed while changing the cambelt as said previously cam box has to be lifted to gain access, so plugs also are removed any damage to plug leads, are earth leads all fitted back on and vacuum pipes correctly .if i had fitted a cam belt and this had occured i would do my upmost to find the cause whether or not it was my fault.take it back to the garage it didnt do it before belt fitted . :ffs:ps still have doubts if belt out a tooth

...when the cam box was removed.

Finally (and I don't really know how you can enforce this?) I would recomend that it is the SAME mechanic that works on/carries out the diagnosis/checks on your car.

Please keep informed, it's something that could affect us all!

Hello All,

Firstly i feel i must apologise for the delay in replying to the latest suggestions, i 've been away for the last week and just got back today 19th.The corolla has been sat in my garage all last week, and took the other halfs battered but reliable Nexia to the coast.

Anyways, i will be taking the car back to Toyota this week and trying to solve the mystery as to my rough running motor, this will be the 3rd time its been in since belt change.

On the mechanic point , it would seem that the same mechanic seems to have carried out all work on the car since i've been taking it to them according to invoices etc so theres a plus point.

Will keep you all informed as to what happens.

Regards

Albi

[/quote

Hello All,

Well since my last post the car has been back into Toyota twice trying to solve the mystery of all above symptoms.I think in total this makes five trips to Toyota .

On the fourth visit, i was told that they had run fuel cleaner through the car and it was now running a lot better , ( i didn't notice any improvement in fact i thought it was a little worse ) but they did also say that they had to order a vacuum hose ( this would take a week to arrive ),they would fit this and see if any improvement, if not, this would mean more investigation.I was beginning to think a hefty repair bill would be heading my way.

In defence of Toyota it has to be pointed out that all the time and investigation work ( except the new spark plugs,which they told me had cured the problems , subsequently proved not to be the case ), was carried out free gratis.

The day of the fifth visit ( 31-08-06) was upon me and i duly took the car in.At the end of the day i rang to find out what ( if any ) progrees had been made, and was told that i could collect the car, and it was now fully sorted .

I went to collect it . Gentleman told me they had once again had the rocker covers off and checked valve timing, etc,etc and all was spot on. Mention was once again made with ref to the new oxygen sensor they had swapped for the old unit ( their database showing that the old one was not switching correctly). As i mention in earlier post the new one made no difference to the poor running and the old one was put back on . The car was now running rich on emmision test. No mention of the new vacuum hose they had ordered though.

Hang on in ther folks we're almost there!

Upshot i was informed, was that the new oxy sensor had been faulty and they had replaced with another one.

The car is now running as it was pre cam belt change, and has behaved itself for the last two days, no poor idling at rest or sudden rpm drops at junctions etc, car is idling at 500 rpm at rest as before.

So we'll see how it goes from here.

I have to say all through this episode i was treated as i would like to be treated, and can have no complaints at all with repect to customer care.

Cheers

Albi

[215 compressor]

I realise I may be repeating myself here, but the faults you incured did seem to point to the Oxygen Sensor, and I am glad they did try changing it ..but then they said no change, fair enough, but ... did they actually take the car out for a RUN with the new oxygen sensor fitted (and not just sat on the ramp idling )?

INFO Picture: Oxygen/lambda Sensor fitted into front section of exhaust on 1998 Corolla 1.6

Also how come the emissions were fine with old Oxygen Sensor, then replace with new sensor, then put old sensor back in and emissions are high? ...this I feel makes no sense. Were they SURE the emissions were within limits the first time?

With regards to the Cambelt change, thankfully this member is thinking along the same lines, as I too wonder more and more if something was wrongly disturbed (even though done by Toyota Mechanic)...

215 compressorreal glad you got sorted you got there in the end

hi i work in the motor trade and it annoys me to hear that you have payed for a job doing and since have this problem it is there responsibilty to find out the cause has it has only occured since they worked on it last .surely something has been disturbed while changing the cambelt as said previously cam box has to be lifted to gain access, so plugs also are removed any damage to plug leads, are earth leads all fitted back on and vacuum pipes correctly .if i had fitted a cam belt and this had occured i would do my upmost to find the cause whether or not it was my fault.take it back to the garage it didnt do it before belt fitted . :ffs:ps still have doubts if belt out a tooth

...when the cam box was removed.

Finally (and I don't really know how you can enforce this?) I would recomend that it is the SAME mechanic that works on/carries out the diagnosis/checks on your car.

Please keep informed, it's something that could affect us all!

Hello All,

Firstly i feel i must apologise for the delay in replying to the latest suggestions, i 've been away for the last week and just got back today 19th.The corolla has been sat in my garage all last week, and took the other halfs battered but reliable Nexia to the coast.

Anyways, i will be taking the car back to Toyota this week and trying to solve the mystery as to my rough running motor, this will be the 3rd time its been in since belt change.

On the mechanic point , it would seem that the same mechanic seems to have carried out all work on the car since i've been taking it to them according to invoices etc so theres a plus point.

Will keep you all informed as to what happens.

Regards

Albi

[/quote

Hello All,

Well since my last post the car has been back into Toyota twice trying to solve the mystery of all above symptoms.I think in total this makes five trips to Toyota .

On the fourth visit, i was told that they had run fuel cleaner through the car and it was now running a lot better , ( i didn't notice any improvement in fact i thought it was a little worse ) but they did also say that they had to order a vacuum hose ( this would take a week to arrive ),they would fit this and see if any improvement, if not, this would mean more investigation.I was beginning to think a hefty repair bill would be heading my way.

In defence of Toyota it has to be pointed out that all the time and investigation work ( except the new spark plugs,which they told me had cured the problems , subsequently proved not to be the case ), was carried out free gratis.

The day of the fifth visit ( 31-08-06) was upon me and i duly took the car in.At the end of the day i rang to find out what ( if any ) progrees had been made, and was told that i could collect the car, and it was now fully sorted .

I went to collect it . Gentleman told me they had once again had the rocker covers off and checked valve timing, etc,etc and all was spot on. Mention was once again made with ref to the new oxygen sensor they had swapped for the old unit ( their database showing that the old one was not switching correctly). As i mention in earlier post the new one made no difference to the poor running and the old one was put back on . The car was now running rich on emmision test. No mention of the new vacuum hose they had ordered though.

Hang on in ther folks we're almost there!

Upshot i was informed, was that the new oxy sensor had been faulty and they had replaced with another one.

The car is now running as it was pre cam belt change, and has behaved itself for the last two days, no poor idling at rest or sudden rpm drops at junctions etc, car is idling at 500 rpm at rest as before.

So we'll see how it goes from here.

I have to say all through this episode i was treated as i would like to be treated, and can have no complaints at all with repect to customer care.

Cheers

Albi

real glad you got sorted you got there in the end.

[Shakul]

First of all I'd like to thank all here for the fabulous reading material. As additional information I'd like to recount my own story of Corolla stalling at traffic lights. (1998 Corolla with 4A-FE engine - 1.6 euro version)

1. It would only stall and die when the engine was neither completely cold nor fully warm.

2. When warm the revs would dip way below the 700rpm but come back up and be ok and steady.

3. Kangarooing effects when taking my foot off the gas were always there and pressing the gas again would cause a noticeable delay.

4. When REALLY warm e.g. after a 200km trip with speeds of 160-170kph (gotta love German highways) the idle would flutter in the 400-1000rpm range until the engine cooled off a bit.

5. The weird part is: when I took the Battery out and charged it overnight the effect would disappear for a few days and later kick-in, gradually worsening. According to all tests the Battery is good though, so I don't expect the Battery to be the root cause.

After 3 trips to different Toyota dealers I've finally been told it's the lambda sensor which will cost me €300 to replace. (gotta hate Dutch prices).

After reading the whole story above my post, I'm inclined to agree with the guys at Toyota and go ahead with the change of the sensor. I've still got a question to whoever might know: In view of point 5, can it actually be lambda sensor?

I've still got to wait for the sensor to arrive and of course if it doesn't fix the problem they'll be switching it back faster than they've put it in.

cheers

Shakul

[Twincam.GTi]

First of all I'd like to thank all here for the fabulous reading material. As additional information I'd like to recount my own story of Corolla stalling at traffic lights. (1998 Corolla with 4A-FE engine - 1.6 euro version)

1. It would only stall and die when the engine was neither completely cold nor fully warm.

2. When warm the revs would dip way below the 700rpm but come back up and be ok and steady.

3. Kangarooing effects when taking my foot off the gas were always there and pressing the gas again would cause a noticeable delay.

4. When REALLY warm e.g. after a 200km trip with speeds of 160-170kph (gotta love German highways) the idle would flutter in the 400-1000rpm range until the engine cooled off a bit.

5. The weird part is: when I took the battery out and charged it overnight the effect would disappear for a few days and later kick-in, gradually worsening. According to all tests the battery is good though, so I don't expect the battery to be the root cause.

After 3 trips to different Toyota dealers I've finally been told it's the lambda sensor which will cost me €300 to replace. (gotta hate Dutch prices).

After reading the whole story above my post, I'm inclined to agree with the guys at Toyota and go ahead with the change of the sensor. I've still got a question to whoever might know: In view of point 5, can it actually be lambda sensor?

I've still got to wait for the sensor to arrive and of course if it doesn't fix the problem they'll be switching it back faster than they've put it in.

cheers

Shakul

HELLO

May I ask what milage (kilometre) your car is at?

Point 5 does concern me ...Alternator problem?

Finally as you can see from all the reading my diagnosis was NOT all quite right that time due to there having been an incorrect cam belt change if I remember correctly as well (must read it all again sometime)

[Shakul]

HELLO

May I ask what milage (kilometre) your car is at?

Point 5 does concern me ...Alternator problem?

Finally as you can see from all the reading my diagnosis was NOT all quite right that time due to there having been an incorrect cam belt change if I remember correctly as well (must read it all again sometime)

Atm it's at 175000 km ('bout 110000 miles)

I thought about alternator problem for a moment but then I'd have expected the Battery to die quickly. It's not dead and in fact the Battery charger does not report the Battery to need any charging. Not so sure about it anymore though.

Still waiting for the sensor, it's getting put in tomorrow morning so I should have the result posted in the afternoon.

I've heard from the guys at the garage that this weird problem is also happening to other Toyotas (in this case they mentioned a Previa and an Avensis).

[Twincam.GTi]

^

When rectified for future reference would be interested to know more