• NAXJA is having its 18th annual March Membership Drive!!!
    Everyone who joins or renews during March will be entered into a drawing!
    More Information - Join/Renew
  • Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

High idle. IAC?

Ben824

NAXJA Forum User
Location
Woodstock, GA
97 XJ 4.0L Auto 4x4

Can a high idle be caused by a faulty IAC? The CEL came on recently and it came back with the IAC code but went off the next day. While the CEL was on the Jeep seemed to be running fine despite throwing a code.

It came back on this morning, assumed it was the IAC tripping the light, but I noticed when I got to work and threw the Jeep in park, it was idling around 1000-1100 rpm.

Could this still be the IAC? I haven't gone back to have the code pulled again but just thought I would ask here than bother going through it again.
 
Yes, it could. Proper diagnostics and troubleshooting starts with knowing, by the numbers, the exact CEL trouble codes present.
 
I spent 3 weeks trying to figure out what was causing fast idle on my 94.
No CEL and the fast idle only happened when it warmed up. It would run up to 1500 to 1700 then come back slowly, and wouldn't idle when it first started cold.
I put in a new IAC yesterday, ALL IS WELL!
 
In my experience a steady high idle is a vacuum leak, and any high idle that sways up and down is a IAC either going out or sticking. When was the last time the throttle body cleaned?
 
Back
Top