Contour Enthusiasts Group Archives Forums General Troubleshooting IAC Installation Question

Are there any special procedures for installing the IAC? I unbolted mine (two 8mm bolts) and it came right off. Didn't even need to clean the gasket off. Put on the new one and the car won't idle. It slows and speeds between 500 and 1000 rpm. I unhooked the battery for ten minutes to reset computer, restarted and it still does it.

I replaced the IAC because the car was stalling at idle. It started doing it after sitting for a few minutes in park. It would idle fine, then stumble, rev to recover, and then clear up. That grew into doing the same thing in drive. The car did it when new, and it was the IAC. So 80K later, I figured it needed to be replaced again.

I took the new one back out, and replaced it with the old one, and it does the same thing as the new one. I checked to ensure I didn't break any wires, unplug any vacuum lines. I have the parts store ordering a replacement. I just want to ensure I am not doing something wrong. I have look at the shop manual I have. It says very little about the IAC, just basically what I stated about installing it.

Runs fine above idle.

Any help would be appreciated.

More than likely you broke the seal of the UIM gasket introducing a vacuum leak there. Try pressing down on the intake to see if the idle clears up.

OK, I went out and tried that. Man it's cold out there.

Didn't make a difference. I don't know how I would have broke the seal on the UIM. The IAC came out to easy.

Any other ideas?

Thanks!

With my experience with them, you almost always need to replace the gasket material, donâ??t ever use the same material twice. Wonâ??t idle as good, I learned that the hard way. Took it off, put the [censored] one back on, and then it still didnâ??t work, found out on here you should replace the gasket material, its very cheap, just go to an auto store and ask for it. 4-5 bucks after tax.

It's a simple enough gasket. I could make one, I have lots of gasket material. If I get a chance, I'll make a new one. Otherwise, I will just wait till the new IAC comes in, it will have a new gasket.

Faulty replacement part always a possibility, of course, but you might want to check the small vacuum hose at the top of the EGR valve. This small hose gets very brittle with age and is easily cracked accidentally when working in that area of the engine.

As you have noted IAC re & re not complcated.

I will get out there this weekend when I can fire up the heater. I can do a better check for leaks up to and including spraying some carb cleaner around the UIM gaskets.

I'll have to use the other car till then.

I replaced my IAC valve yesterday to cure the same problem (stalling instead of idling) and it has worked pretty well. Definitely check the vacum hoses to make sure everything is air tight.