Hi guys I have a problem with my new Cherokee. I just bought this jeep with 176,000 miles. It has a high idle issue, it idles around 1400 RPM. I bought a new MOPAR IAC and it still idles the same. I also replaced the TPS with an Autozone part. I have checked the continuity of the harness and it checked out good. The only other thing that I can think it might be is the PCM, or maybe a fuse/relay? Does anyone have a suggestion because it is driving me insane. Oh and the gas gauge doesn't work probably not connected though? any help will be much appreciated. Thanks

 

Help us remember what year this Cherokee is, and what engine and transmission it has.

First observation is the TPS from Idiotzone is probably bad out of the box.

It's not the PCM and it's not a fuse.

Check all vacuum hose connections and tubing/hoses in the engine bay and make sure they are secure and /or not cracked/deteriorated.

 

Have you checked for loose intake bolts its very common for them to work there way loose causing a vacuum leak which raises the idle.

 

My appologies its a 2000 4.0 automatic. Thanks The reason i dont think its the TPS is because I took the old IAC and pulled the pintle out by hand until I got it to idle where I wanted it to. When i put the new one in it goes to the 1400 rpm idle.

 

Why did you replace the Iac originally ?

 

I have checked all the vacuum lines with brake clean no change in idle. I have not checked the intake bolts I will do that in the morning when i have some light.

 

I changed it originally because of the high idle.

 

Check bolts deff...

 

ok i will check intake bolts. also how mant volts does the IAC get, because only one of the 4 wires showed voltage and it was .5 volts

 

Is check engine light on ?

 

Yes it showed a p0505, p1694 no CCD messages recieved from ECM. and p0123

 

Im renix powered so not quite sure if yours is same..should be info here.....http://www.jeep4x4center.com/knowledge-base/index.htm

 

Thanks

 

It sounds like something is going on with your IAC but keep in mind you do have an idle adjustment 3/16" Allen head on the front driver side of your throttle body. It's usually threaded in from the bottom so u have to pull the TB off to adjust. Just an idea.

 

Well I checked all the intake bolts and they were tight. I have sprayed nearly 2 cans of carb cleaner on everything and there is no vacuum leaks. So I just took the old IAC Valve manually pulled out the plunger until I got the idle about 900 rpm and pulled the fuse that makes the Check Engine Light come on. I guess if I want it fixed I'm gonna have to take it to the Dealer. It just makes me mad because I can usually figure this stuff out.