Today I drove my Jeep to the store and I could hear my intake sucking in air like I was on the freeway. It was wet outside so I had to defrost the windows so when I put the de-frost on, the air intake doubled and the rpm's shot up to 2500 at a dead stop while in gear. I put it in park to shut it off then the rmp's shot up to 3500! I have already replaced the IAC with a new one about a month ago and cleaned the throttle body (Shinny clean). It also had a new TPS too. 88 cheokee 4.0 any idea's. Thanks

 

Sounds like a vacuum leak. Take the TB back off and tighten everything back up. Sensors, IAC , etc. Get a new TB gasket (felpro).

 

ok I will get the gasket but I sprayed throttle body cleaner around all the spots where I thought a leak could be and the idle stayed consistant. Thanks for you advice.