[ramvan1986]

I have a 1996 Jeep Cherokee. Manual transmission. When shifting, idle speed hangs up [idle high] and this causes drivability problems. Esp. when going from a stop light into first gear. Have replaced IAC motor, TPS and have checked all vacuum connections.

Also have checked engine ground wire. Problem seems to be intermittent but happens too much.

Any ideas out there on what I should check. Thanks.

Ramvan 1986

 

[Bob Lincoln]

Most common problem is a vacuum leak. Check all tubing, both rigid and rubber, for cracks, and check for leaks around the throttle body. Spray around the base of it with carb cleaner and see if the idle changes. Make sure the bolts are tight.

 

[ImperialCrown]

Agree. These also didn't use a PCV valve, but more of a valve cover vacuum orifice for crankcase ventalation.
It is important that these are clear to draw crankcase fumes as they often plugged up or restricted.
The throttle body blade and bore must also be cleaned of carbon build-up periodically.