Revving Sounds When Idle And Switching Off

November 29, 2010

First of all i apologise for not being that smart with my knowledge about cars.

For around a year now my 52 plate 1.0 Yaris revs by itself when standing still at lights for example. Local garage said its nothing to worry about so i ignored it.

Then 2 weeks ago the car cut out completely 3 times on a short 10 minute early morning drive through inner city roads where i stopped on 3 occasions. Also the orange engine maintenance light came on. I took it straight to the garage who attached a computer to it and the mechanic told me that the Air Flow Sensor needs replacing but that this problem will happen only when it is cold in the morning. He managed to get rid of the orange light and told me to bring it in a day or 2 later while he finds the part for me as for now its not dangerous to drive and wont cut out again. Sure enough i drove the rest of the day with no switching off.

Since then i noticed it switching off early in the mornings on the odd occasion but as the mechanic hadn't managed to get hold of the sensor i thought id check around a few scrap yards for the part myself.

Today i found the part that i needed and asked the guy at the yard to fit it in for me. Straight away the car switched off after around 5 seconds. This was worse than the sensor already in place before, which incidently looked fine and clean. The guy told me that this part was not the problem and that the strange sound the car was making is being caused by something else.

This sound is the same sound i heard originally when the car used rev by itself. So i assume this is all linked to original problem of idle revving. The sound is a sort of swooshing air sound.

Can anyone point me in the right direction as to what might be wrong? Is something loose? blocked pipes?

Your help is greatly appreciated. I feel like selling the car and buying something else if its expensive to sort this out.

November 30, 2010

Sounds just like a problem i had with my Accord last year. The EML light came on and caused the car to run erraticatly, the revs would drop and it kept cutting out when slowing for junctions, traffic lights ect but when driving along normally it was fine, then it would occasionally stutter and hesitate.

I took mine to the dealers and the fault was the 02 sensor, New one fitted, EML light out and no more problems.

Does the car need servicing, ie air filter and spark plugs ok? Ask your mechanic to check the lambda and 02 sensors, maybe thay can be carefully removed and cleaned with brake or carburettor cleaner and try them again.

Wouldn't have thought it to be too expensive a job even if it needs new sensors. I paid about £200 all in for the diagnostic check, buying the 02 sensor and then for the Honda mechs to fit it for my Accord so it might be similar for your Yaris but i couldn't say. That was at the dealers though but you might be able to get it fixed cheaper at your local garage.

Good luck, keep us posted! :thumbsup:

November 16, 2018

Try just cleaning (not replacing) the Mass Air Flow Sensor $5-$10, replace the PCV Valve $10-$15, disconnect the Battery completely wait 5 minutes and reconnect. Drive about 50 miles and it should recallibrate. Have O2 sensors checked if this doesn't seem to do the trick.

This is a problem many Toyota owner's are facing. A mechanic friend gave me a suggestion that cleared up the problem for about 40,000 miles, but it just started up again. I changed out the PCV Valve, and Cleaned out the Mass Air Flow Sensor. Had to hard disconnect the Battery and drive about a hundred miles afterwards before the problem went away. But it did so for the last 40,000 miles (about a year's worth of driving). Just started having issues again after this last oil change. Mine is a 2009 Yaris Sedan with 301,000 miles on it.

https://youtu.be/047xItGmNH8

https://youtu.be/YnckaCCJEEk

https://youtu.be/2pCqmw3yWng

https://youtu.be/7f2WX8AeJfI