My rig has a really bad high idle issue in the cold. I changed my tps and I cleaned the throttle body but it is still really bad. I would love any suggestions on how to fix it (preferably cheapest first).

 

how high is high? mine idles at 1k when i first start it up. cold start valve.

 

It is high enough to diesel really bad after i turn it off

 

Have you cleaned the iac?

 

I put a new one in not long ago. It didnt make a difference.

 

Spray around the intake and such with carb cleaner, looking for a vacuum leak? Could be a minor leak that seals as the parts heat up and expand.

 

how would I find a leak?

 

If there's a leak the engine will suck the carb cleaner in (through the leak) and the idle speed will change momentarily.

 

I'm guessing bad TPS on the engine side, and/or bad sensor ground circuit.

If it were mine, I would first do a complete ground refreshing #1 in my link, the C101 cleaning #2, connector refreshing #3.

 

Thanks. Just to clarify, it doesnt idle high right when I turn it on. It starts fairly normal but after I drive it gets stuck in high.

 

Currently having the same issue with my 89. I also have an issue with fuel. Not sure if they are related. When I first start the jeep sometimes it will jump to 2800 rpm. And will stay. I have to shut it off and restart it. Then it will idle below 1k. But once I get to my destination it will be idling at around 1500. It has been cold out. But I'd doesn't matter on engine temp. Which brings me to my fuel issue. It takes longer to start then normal. Unless I prime it. Key on and off a few times. I was thinking a leaky injector. But these could be two unrelated issues.

 

Either way, do the procedures outlined that I posted.

 

I've got a high idle issue too. Kinda weird. Sometime when I start it the idle will be up around 2200 2500 and after about 5 seconds or so it will go back down to normal. Doesn't always do it. Does it cold or hot. Any ideas?

Thanks

 

Thanks for your post.
We’re here to help but you must understand that all Jeeps are not the same.
In order for us to give you more accurate advice and help, we must know the following, along with detailed information as to the symptoms/problems etc:
Year
Model
Engine
Transmission

 

Yeah I guess that would help. 88 4.0 auto