Corolla hesitation/misfire

[Pete Corolla]

Hi, I have a 2006 Corolla with a 1.6 VVTI engine.  The car has only done just over 70000 miles but recently has developed an annoying habit.  When on a low throttle opening it feels to hesitate/misfire/almost cut out.  Give it more throttle and it picks up fine again.  It doesn't do it all the time, and doesn't seem related to engine temperature.  If it was something like a sensor that has failed I would expect a warning light of some kind, but there are no warning lights appearing. If it was a pre-electronic car I would say fuel starvation.

Please can anybody advise what might be causing this?  Ideally I don't want to go to a local garage as a) it would probably cost more than I want to spend, and b) I am English living in France and my French isn't good enough to discuss techie stuff with a French mechanic😂

Thanks for any ideas.

[TonyHSD]

Hi, 

common issue with engine response and general work comes indeed from air fuel mixture. You can check air filter, spark plugs , exhaust pipe if dark , black soot or oily, throttle body and sensor next to it, only check, clean and replace with new parts only if you are sure that the part in question is indeed faulty. Just do the usually service,  new oil and filters, and if still the same you can add a fuel additives and take the car for a motorway run of 30-40 min at high speeds , no need to exceed spied limits but good constant high rpm 2500-3000 help rise temperature and clean exhaust system, catalytic converters, lambda sensors. You can try wynns catalytic converter and lambda sensor cleaner, this is great product. Add in max 30ltr of fuel otherwise may not work. If you decide to do that few fast acceleration are also recommended middle of procedure to rise the pressure and blow off any soot accumulation in the exhaust system. Cars regularly driven on motorways never need this but those used in town’s mostly and on short trips will benefit a lot. 👍
https://www.ebay.co.uk/itm/393432200811?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=MQfZam35TmK&sssrc=4429486&ssuid=p34UK1z2T4m&var=&widget_ver=artemis&media=COPY

[Pete Corolla]

Thanks!

I'll try and source that here and give it a go.

[oldcodger]

If you cannot get that Wyns cleaner locally, have a look for the similar CataClean which has been around for some years.

[AisinW]

22 hours ago, Pete Corolla said:

Hi, I have a 2006 Corolla with a 1.6 VVTI engine.  The car has only done just over 70000 miles but recently has developed an annoying habit.  When on a low throttle opening it feels to hesitate/misfire/almost cut out.  Give it more throttle and it picks up fine again.  It doesn't do it all the time, and doesn't seem related to engine temperature.  If it was something like a sensor that has failed I would expect a warning light of some kind, but there are no warning lights appearing. If it was a pre-electronic car I would say fuel starvation.

Please can anybody advise what might be causing this?  Ideally I don't want to go to a local garage as a) it would probably cost more than I want to spend, and b) I am English living in France and my French isn't good enough to discuss techie stuff with a French mechanic😂

Thanks for any ideas.

If there is no check engine lights from misfire, 3 Things to check first: 

1.  Clean the Mass Air Flow (MAF) sensor with 99% Isopropanol spray or  non-acetone brake cleaner. (10 minutes DIY)

2. Clean the throttle body, especially the lips of the batterfly flap and the cylinder wall where the flap meet.  (30 minutes DIY)

3. Replace the iddler air control valve if it is indeed broken. But do the first 2 step first. Ask mechanics to check this part first. Don't change things randomly and always use Original Toyota part for this. 

These problems often do not cause Check Engine Lights. 

  

[Pete Corolla]

Would carburettor cleaner be OK to clean the MAF sensor?  The Youtube video I watched said that is what to use.

[AisinW]

@Pete Corolla You can use anything tha left no residue, not harsh to copper wire and plastics.  Carburator cleaner often contain acetone and acetone is harsh to plastic and worse to polycarbonate (microcrack in headlights).  I think most brake cleaner are safe for mild usages, don't submerge the sensor in it.  Just spray it a bit. Take a look if you see no black coating  or dirt. The delicate wire on the sensor should be shiny. 

Ideally we use MAF cleaner (contains no acetone nor oil) because electronic cleaner are often contains silicone oil to lubricate the electronic join. This silicone layer will cause trouble in MAF because hinder the temperature reading. I learned it hard way on my Auris 2.  I managed to clean it with 2-3 spray of non-acetone base brake cleaner. 

[oldcodger]

Holts Prof Brake Cleaner, stating Acetone and Silicone free,   should be good if you can buy it in France ?

https://www.holtsauto.com/holts/products/brake-cleaner/

[TonyHSD]

1 hour ago, oldcodger said:

Holts Prof Brake Cleaner, stating Acetone and Silicone free,   should be good if you can buy it in France ?

https://www.holtsauto.com/holts/products/brake-cleaner/

This is the best one and the only one I use. 👍

[Pete Corolla]

Thanks everybody - I have ordered this : Amazon.fr : Holts Nettoyant Freins 600ml

Let's hope it works.

The day before yesterday I added some Wynns Force 6 to the tank and as the issue was intermittent it's hard to tell, but that might have improved things.

When the cleaner arrives I'll clean the MAF sensor and let you know what happens.

Thanks again.

[Yugguy1970]

I've always liked these:

https://www.ebay.co.uk/itm/362505484376 for petrol

https://www.ebay.co.uk/itm/175325632984 for diesel

 

[TonyHSD]

Good to here some improvement. 
Another idea when you are cleaning sensors and throttle body, use only specific spray made for those and before you commence any work a good practice is to disconnect negative terminal of the 12v Battery during your work. The reason is to re set all ECU’s to default settings. 
When you finish your work, make sure all wire harnesses are properly clicked in place and then reconnect the Battery.
Before you attempt to start the car turn ignition into ON two turn of the key to two press on keyless start button, all lights should come on, switch off all accessories like heating, interior lights, radio etc, and now turn off ignition. 
Turn to ON position again and wait 5 seconds, turn off again and wait another 10 seconds. Now you can start the engine as usual and let it idling for 15 min without touching accelerator, brake, steering wheel or use any accessories and turn off . Then after you are free to start and drive or use anything. The next few start and drives 4 or more the engine might run rough and unstable at times but this will settle soon after if everything it’s ok.
The process called relearn throttle position and all other sensors parameters. Not necessarily to any male and model but in many cases help eliminate those rough idle after cleaning procedures. 
Good luck 

[Pete Corolla]

19 hours ago, TonyHSD said:

Good to here some improvement. 
Another idea when you are cleaning sensors and throttle body, use only specific spray made for those and before you commence any work a good practice is to disconnect negative terminal of the 12v battery during your work. The reason is to re set all ECU’s to default settings. 
When you finish your work, make sure all wire harnesses are properly clicked in place and then reconnect the battery.
Before you attempt to start the car turn ignition into ON two turn of the key to two press on keyless start button, all lights should come on, switch off all accessories like heating, interior lights, radio etc, and now turn off ignition. 
Turn to ON position again and wait 5 seconds, turn off again and wait another 10 seconds. Now you can start the engine as usual and let it idling for 15 min without touching accelerator, brake, steering wheel or use any accessories and turn off . Then after you are free to start and drive or use anything. The next few start and drives 4 or more the engine might run rough and unstable at times but this will settle soon after if everything it’s ok.
The process called relearn throttle position and all other sensors parameters. Not necessarily to any male and model but in many cases help eliminate those rough idle after cleaning procedures. 
Good luck 

Hi Tony, I am now a little confused.  Further up this thread you recommended Holts brake cleaner, which I have ordered, but now you are saying only use a sensor specific cleaner?  Will I be OK using the brake cleaner?

Thanks.

[TonyHSD]

3 hours ago, Pete Corolla said:

Hi Tony, I am now a little confused.  Further up this thread you recommended Holts brake cleaner, which I have ordered, but now you are saying only use a sensor specific cleaner?  Will I be OK using the brake cleaner?

Thanks.

Hi, 

this holts is very good and safe on most parts, metal or plastic. 
I can’t say for sure it is safe for all sensors though. Some cars require specific spray for each job that’s why I mentioned it. 
I have used Holts egr and throttle body cleaner and wynns carburettor and egr cleaner plus this holts brake cleaner on Auris hybrid for maf/map sensor next to throttle body, throttle body itself, brakes, and all other parts on the car to clean grease, soot or oily formations. I had no issues so far. You can try with this holts brake cleaner or buy specific spray for each job, it’s up to you. 

[Pete Corolla]

Thanks again!

[TonyHSD]

9 hours ago, Pete Corolla said:

Thanks again!

You are welcome. 

[Pete Corolla]

Having dosed the wee beast with Wynn's Force 6, and cleaned the MAF sensor my little car is now running like a Toyota should!

Thanks you very much for all your help.