My '89 does the same thing, warm or cold. Idle
is not adjustable and my mech isn't concerned
about it. Still does the fluctuation when engaging
the ac compressor with no sweat!
I have a 91 TBird with the 5.0L HO engine and AOD. It suddenly developed a
high idle. I checked the linkage, nothing is binding or hanging up. I even
unhooked all the cables from the throttle body, made sure it was closed and
started it. High idle.
It idles about 2000 rpm. At first it would only idle high a few seconds when
you first started it up. Now it idles high, ALL the time.
I pulled apart a few wiring connectors and all the contacts look clean on
the idle air solenoid, TPS and maf sensor.
What could be wrong and how should I check it?