My cars idles pretty rough (swings back and forth) when the car gets hot. I ended up taking off the IAC valve and cleaning it. It was very dirty, bunch of carbon build up looks like. However, the problem still remains. Is it possible that the valve itself is no longer functioning correctly? Is there a way to test it? I would rather not just buy one in hopes that that is the problem. Any help would be appreciated.

 

ttt
i am also interested in this i havent taken mine apart yet but my car idles really low around 550 and if i rev it up too hard itll stall when i let it down and occasionally it stalls at a light in traffic. So how do you test it?

 

I don't believe you test it, but the length of it has to fall in a certain spec.
Don't forget to clean the passages in the TB as well.
I had the same problem, cleaned it, was a little better, then replaced it and all was good.

 

Seems like these IAC valves are very sensitive to dirt. This will be about the 3rd or 4th IAC valve since I bought the car. I was just hoping that it was something else a little cheaper this time, but it's probably it. After cleaning, it did get noticeably better, but still not perfect. I did clean all the little passages in the TB. What I don't understand is how does it get so friggin dirty in there? I also looked inside the plenum and it was just filthy. I cleaned it out with that spray cleaner. I guess I'll be blowin another 50 bucks on a damn IAC valve....

It must be isolated to these cars as my other cars, 99 Cobra and 92 Camry (wow, I must have something with cars that start with Cs...) never get so dirty in the intake. Must be a Chevy thing.

 

Blame the EGR and the blow by return.
After you clean the plentum block off or unhook the vaccume line to the EGR so it stays clean.