Toyota yaris 1.3 vvti 2000, stutter.

[YokoOhno]

I am trying to fix my toyota yaris, took it to a Toyota mechanic. They said there was an issue with the computer but didn't want to replace it because the car wasn't worth it.

I replaced the computer but it didn't fix the issue. Also replaced the MAF sensor. Still the car shows no signs of improvement. Now I'm guessing it's caused by the throttle position sensor, because the housing was already cleaned.

Can somebody tell me how to replace / clean this sensor. Or can someone help me in diagnosing this problem. 

[bathtub tom]

I think we need to know what the problem is.

[m456an]

If the problem is revs going up and down I fixed this on my Avensis by cleaning the PCV valve. Though most would have returned the car, but it was a cheap fix.

Dealers and garages do like to replace parts rather than clean things.

If the MAF sensor has been replaced it can be assumed the throttle body has been checked and cleaned.

[Madasafish]

Basic tests are: check plug gaps, check air filter,check oil is clean (if not the VVTI mechanism - driven by oil pressire - may not work properly)

 

You don't mention those: which cost nothing to do.

[gebe717]

I had a similar problem on my old 1.3. In my instance it was a combination of things contributing to the issue. Ultimately it was a vacuum leak. It's the rubber hoses going from the fuel filter to the blue solenoid (mounted on side of the airbox) ,and then on to the inlet. They crack at the ends and sometimes in the middle. Also best to check the 2 oil breather hoses and the throttle body o-ring gasket thingy.  

Cleaning the connecter for the MAF sensor helps. When you reconnect, give it a good hard wiggle to assure contact is being made inside.  

As someone else commented, it "might" be a VVT-i problem. In my experience, when these fail, you just loose a bit of power down low in the rev range as the camshaft is not advancing. However, when you get to about 2400(ish) RPM everything is normal. 

It might also be a bad stick(?) coil. The OEM Denso units aren't cheap. However, it got 4 from a breakers yard for £20.