95 APV high idle

95 APV 3.8 engine. At times engine has a very high idle, 1500-2000 rpm. IAC is reading 103 and is non responsive. TPS also shows 3% and .45V. This thing is driving me crazy. No codes are set and I can cycle the key fast enough to stay running and everything returns to normal, IAC will run up and down with scan tool. But when it's acting up it just freezes at 103. PCM maybe? Had a problem a while back that has now since disappeared. Engine wouldn't run when trying to start and CEL would flash very rapidly like a power relay was fluttering. May be connected problems??

Look for a vacuum leak. Hoses, intake manifold.

No vacumm leaks. Problem is intermittent and unpredictable. Almost seems that ecm looses control of the IAC. Haven't pulled IAC and cleaned it yet, really not sure if that is it.

Clean the IAC and the throttle plate.

Just an update. Cleaned the IAC good a few days ago and it seems to have taken care of the problem. Didn't want to pull the TB to clean it good so I just soaked it down as best I could. IAC counts seem to be down to a lower level now also, around 15 at idle in D, no a/c on.