How do you test the IAC?

[porshapower]

I have the 96 with the idle tremble sputter. It only does it at idle. It is the 4.0 motor. Have replaced airfilter,cleaned the maf twice,new egr valve,new egr pressure sensor(dpfe),new plugs,wires are good,coil is good. Rans seafoam through it twice and techron. I cleaned the iac today and it looks clean inside (spring and little sensor). Anyway to actually test it before I throw more money at it. Checked for vacuum leaks. Sprayed carb cleaner all over this thing today and nothing smoothened it out. Sprayed carb cleaner into throttle body to see if it would possible be an intake leak no suck luck. I am running out of ideas and have no check engine light on. When you accelerate its perfect. Only when it sits at idle. ThanksNel

 

[dogfriend]

It is possible that the valve inside the IAC is sticking closed, even if it tests ok electrically. My IAC valve was sticking after the engine was warm, so that it wouldn't idle after restarting with a warm engine.

A quick and dirty test is to pull the connector off the IAC while the truck is idling. If it is working, you should get a drop in the idle speed. If there is no change, it isn't working.

I demonstrate this in this video:

http://homepage.mac.com/dogfriend/iMovieTheater14.html

 

[IAmTodd]

Go buy a new one. They're only around $50. Your Explorer will thank you