Re: Weird Problem...Maybe Someone Can Help?
The IAC is a motor-operated air valve. It has evidently changed position while it was plugged in and now is farther open. I would plug it back in, let the engine warm up and set the idle to normal, then unplug it. I think it can be manually re-positioned, but that may damage it if not done carefully.
1998 Trans Am, LS1, Automatic, stock all the way.