Does your engine have individual injectors, one per cylinder; or is this a TBI (just two injectors inside a throttle body)? The latter would not have an IAC, but a servo-motor which controls the throttle idle stop. They have a switch at the tip which likes to go bad, resulting in the computer not knowing that you took your foot off the accelerator. It could also be a vacuum leak, an EGR valve that won't close, or a bunch of other reasons. Do yourself a favor and read the trouble codes first before guessing. All you need is a paper clip and possibly a test light.
Sounds like a failed or clogged IAC valve. It's a plunger-type device that
> controls the idle speed and when it clogs, the engine runs like crap at > idle.