Rough Idle / Hunting / Stumbling / Shaking Fix

[Chwbcca]

Hey guys!
My 2007 Yaris has 272k miles and it's still rock solid. I'm sure most American Yaris cars are getting up there in age and miles. I've done tons of work on mine to get it running smoothly and the one thing I have to do often is to clean the throttle body. Yes, it's that easy.

CLEAN THE THROTTLE BODY

It's very simple and easy to do and it will hopefully solve your idle woes unless you have other vacuum or fueling issues or other major issues. If you're on a budget and have some free time clean your throttle body. Takes a 10mm socket, taking off a few hoses and your air cleaner top and then you're in. Remember to not scratch the throttle plate itself with metallic objects. You can open the throttle manually or with the pedal if the car is on. Use a little of carb cleaner or similar and clean it nice and proper. Don't forget the edges of the butterfly itself because carbon sticks there too.

That's it! That's all there is to it.

And yes, you have to do this every 6 months or so, not sure why it gums up so quickly but mine does.

Enjoy your smoother idle!

[komichal]

Let me add a few tips:

- If your car opens the throttle body flap via electric pulses and not mechanically (my 2007 Yaris with 2SZFE does) you should never open it with your fingers but use only the gas pedal with the key set to first position (not running engine).

- Once your throttle body is clean, disconnect the battery for a few minutes. That way you reset the computer and it will reset also the flap position - throttle body then learns the new minimum value for the flap.

- If you want to go the extra mile, remove the whole throttle body from the car (usually just a few bolts) and clean "the other side" as well. While it is not that necessary (the key area is around the edge of the flap and the tubing around the flap) it will make you feel better. :)

- There is also the MAF sensor very close to the throttle body. When doing throttle body cleaning, it is good to clean the MAF sensor too as it weighs the air and measures its temperature before it enters the engine. But beware - MAF sensor is extremely sensitive so you should always use spray exactly prepared for this purpose ("MAF sensor cleaner" or something, usually for some 10 bucks). Just take the MAF out (usually two screws and one connector), spray the inside like mad, let it dry, put it back. It is good to do this with the battery disconnected otherwise you may get "check engine" light on when the computer notices the MAF is disconnected.
I usually buy a can of MAF sensor cleaner and use it to clean the MAF as well as the throttle body. I do not care that it is "too good" for the throttle body - I do not need to store too many unfinished cans in my garage.

[IndestructibleYaris]

Nice write up