2000 tacoma 2.7 idle issue

Ok so when I am at idle and the motor is warm the idle goes quite a ways down and and then goes back up to like 2000rpms and then slowly goes below till it idles ruff and then goes back to around 2000 rpms again..what could be causing this ? I cleaned the pcv valve today and checked for vac leaks which I didnt see any. would this be the IAC valve which I dont even know where it is or how to clesn it on this motor lol ?

 

The IAC is near the TPS, at the bottom of the throttle body. Kinda hidden.

The TPS could be faulty as well. If you have access to a Scanguage or Ultraguage, the TPS output can be monitered. At idle, or any other steady go-pedal position, the TPS output should not change.

 

I know if my defog is on this happens i thought I had a problem..

 

Oh ok whats the defog ?

The IAC is near the TPS, at the bottom of the throttle body. Kinda hidden.

The TPS could be faulty as well. If you have access to a Scanguage or Ultraguage, the TPS output can be monitered. At idle, or any other steady go-pedal position, the TPS output should not change.
__________________
Rick

Hmm so can you clean the AIC with carbcleaner ? I am going to do the free things first lol

 

If your set on defrost the AC kicks on off revvig the engine up when AC turns on for a few seconds..

 

Hmm oh ok maybe thats what is happening. I will see what happenes when the defrost is not on thanks man.

 

Mine use to do this after i had it on the high way the RPM would go up an down from 800-2000 until i started moving again. Sometimes it would hold a solid 2000rpm and other times it would dip down too 325 and i'd blip the gas and get fuel knock from it almost stalling. I just replaced the IAC OEM unit it was around $375. Don't skimp out on cheap part store parts get an OEM one and you wont have any issues. It took a long time for me to figure this out but I finally diagnosed it.