I'm having trouble with a stock 91 idling after it gets up to temperature. When cold, the car starts fine and idles as it is supposed to. I can drive it and get it up to temperature and it idles fine. Zero issues. If I cut the engine off and crank it right back up, it idles at around 2000 and will not come down.
I have placed a solid gasket in Idle air circuit on the manifold and it has zero effect. I currently have the throttle body off as I was checking the IAC valve. The coil is reading 20 ohms. Will a bad IAC cause high idle? I was thinking that it was the other way around.
I find it odd that the cars runs fine until switch it off and back on again. It seems as that would rule out a vacuum leak also and maybe points to something electrical?
Any ideas would be appreciated.

 

OK, I found a used IAC on an old motor. The coil measured right at 12 Ohms. I read on these forums where someone else had a bad coil that measured around 20 Ohms. Anyway, I swapped it out and the problem went away although it still idles right at 1000 rpm. I guess these valves when they go bad can generate a wide range of symptoms.