I've got a '96 JGC with the 4.0 that has recently developed an issue with the idle speed increasing as it warms up. I've checked for vacuum leaks... didn't find any. Cleaned the throttle body and linkage (cables). I also cleaned the port for the IAC/AIS motor as best I could and re-assembled the IAC. Didn't seem to make a noticable difference. I purchased and installed an aftermarket IAC from NAPA and upon starting, got a "Service Engine" light immediately. The code was AIS system malfunction (0505 ?). So I reset the SE light and re-installed the original IAC and started it up again. No SE light, but the idle condition was the same as before... normal upon starting, then increasing as it warmed up. Repeated the same procedure just to make sure I got the same results again. Same same.

I'm going to return the NAPA IAC motor and am thinking about purchasing and OEM AIS motor from the local Chrysler/Jeep dealer to see if theirs gives me the same results. I've read in this forum about an IAC solenoid. Where is this soleniod located? Perhaps mine has failed and it's not the IAC/AIS motor? Any other thoughts or suggestions?

TIA,
Steve