Rough Idle, Loss Of Acceleration & Stalling!

[innocent]

My wifes MR2 Mk3 (with 1ZZ-FED) has picked up a problem - has a rough idle which will drop away to stall if allowed, and doesn't give any power when pulling away unless the revs are held above 2000! These issues are only aparent when its started, warm or cold (but mainly when cold) and last for about 30 seconds to a minute then seem to be ok once the engine's up and running (even if not yet at full temp). Once its been driven a bit you can sit with it idleing for as long as you want and it wont stall and pulls away fine.

I've cleaned out the throttle body and it now idles a bit more smoothly but will still stall if allowed and other problems are still apparent. After disconnecting the Battery and cleaning the throttle it ran perfectly for 3 starts, but once the ecu had re-learnt the engine it picked up the same old bugs.

I've noticed the thread on cleaning the MAF and will give it a go, but i know nothing about engine management so will be stuck if this doesnt work.

Anybody have any suggestions?

Also, i want to check if the ECU is factory standard or whether the first owner gave it some work. Any suggestions how i can check this?

Cheers

[GIDDLEPIN]

I would try cleaning the MAF sensor and re set the ECU (I just disconnect the Battery for ten minutes), then let us know what happens

Les

[compressor mad]

sounds like a maf sensor to me those are the simptoms

[innocent]

Sorted! Cleaned up the MAF sensor on monday night and its run perfectly since. Thanks for the info in your MAF sensor thread Les, you've saved me paying out for the toyota mechanics to scratch their heads and come up with nothing!

Does anyone know how i might identify the ECU as factory or custom?

[T_T]

hiya mate - i might have a problem caused by the same thing, where is this MAF sensor thead please?

[cfc1]

hiya mate - i might have a problem caused by the same thing, where is this MAF sensor thead please?

Hi T_T

Check out the info here under "MAF Sensor"

[T_T]

cheers cfc1 mate :D

[k1sr]

Hi Guys,

I'm having the sam problem - car idles really slow, then stalls everytime I come to a stop - I tried cleaning the MAF sensor, but I'm still having the same problem...

This is something that's happened all of a sudden - happened just once a week ago, now it does it every single time I come to a stop...

Any ideas...?

[GIDDLEPIN]

Hi Guys,

I'm having the sam problem - car idles really slow, then stalls everytime I come to a stop - I tried cleaning the MAF sensor, but I'm still having the same problem...

This is something that's happened all of a sudden - happened just once a week ago, now it does it every single time I come to a stop...

Any ideas...?

Hi and welcome to the club

It could be any one of a number of things to be honest :

Is there a CEL Showing?

How is your oil/water/fuel consumption?

Are there any nasty noises?

Has the car been serviced regularly? if not it might be due one

If everything is ok then you could try an ECU re-set, just disconnect the Battery for 10-15 minutes then see what it's like.

Good luck and let us know how it goes

Les

[k1sr]

Thanks Les,

Yeah, it is due a service, although only a minor oil change...

No CEL either - although I read on the forum about an ECU reset process that might just do the trick - so I'll give that a go...

Simply leaving it disconnected from the Battery for a while (1hr) didn't seem to work...

Cheers

[Mad-Matt]

I'm new to the MR2, but with other cars I'd also be looking at:

1. Cleaning the throttle body.

2. Cleaning the idle valve (sometimes the solenoid that operates the idle valve gets stuck or the gasket where it joins can crack)

3. MAF sensor, as mentioned already.

Finally, if it happened suddenly, was it a tank of "dirty" petrol?

Just some ideas.....

[k1sr]

Quick update...

Cleaned the throttle body, cleaned the MAF, reset the ECU, ran the idle "relearning proceedure" (http://spyderchat.com/forums/index.php?showtopic=52275) and all seems fine...!

Let's just hope it lasts...!

Thanks...!! :D :D :D :D :D