I posted a few weeks ago about a problem I fixed with the MAF ( leak after the MAF ). 89 GT 111k miles, ( car restored to showroom condition ) Last week I pull to a stop light and idle is at 2000 RPM.
Shut engine off and restarted andl all was well, and idle back to about 800. I know something was wrong before hand as the car was pulling without my foot of the throttle. This happened again when I pulled into my driveway so let it run like this and when I pulled the plug on the IAC and idle dropped to about 600.
I took the IAC off the TB and cleaned it which did not look too bad. Installed IAC but left it disconnected and set up the idle on the TB according to the shop manual to 750 RPM. Shut engine off connected the IAC and followed the instructions in the manual to reset the ECU by disconnecting the battery for a few minutes, letting it idle for 2 minutes shut engine off then restart.
Well it was good for 2 days then started the same thing, 2000 rpm at idle…for the time being I have the IAC disconnected and set the idle up on the TB to about 850 RPM.
I have been driving the car like this for 4 days now and no running problems what so ever. Funny thing is no check engine light and no stored codes during this entire episode…Had my friend with an earlier OBD scan for codes and clean.
I hate shot gunning parts by replacing the IAC. Does it hurt running the car with the IAC disconnected or should I foot the bill and get a new one ? and hope that is the problem…or could something else be causing this ?
I checked for any vacuum leaks using my propane torch no change in idle.