Hey guys my jeep would stall and run rough at stops. When I first start the jeep up, it idles fine, but after that it runs like crap at idle. I already cleaned out the IAC. Should i try purchasing a new IAC or new spark plugs? or any other recommendations?

 

anyone?

 

whats the throttle plate look like ,is it sooty around where it seats in throttle body ?

 

yeah but i tried cleaning it good

 

Here's the correct way to clean the IAC and TB.

Have you ever looked at the spark plugs? They're supposed to be replaced every 30,000 miles.
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The Idle Air Control (IAC) is mounted on the back of the throttle body. (front for 87-90) The valve controls the idle speed of the engine by controlling the amount of air flowing through the air control passage. It consists of a stepper motor that moves a pintle shaped plunger in and out of the air control passage. When the valve plunger is moved in, the air control passage flows more air which raises the idle speed. When the valve plunger is moved out, the air control passage flows less air which lowers the idle speed. Over time and miles, the IAC can get carboned up which can have an adverse affect on idle quality. Cleaning the IAC may restore proper function and is an easy procedure to perform and good preventive maintenance so it is never a bad idea.

CLEANING THE JEEP 4.0 IDLE AIR CONTROL

Remove the air filter cover, associated hoses and the rubber boot that goes from the air filter cover to the throttle body. Remove the IAC with a torx driver (2 bolts; one can be kind of hard to get to)

"Gently" wiggle out the IAC from the throttle body. Gasket on the IAC can be re-used if it is not damaged

Clean the IAC with a spray can of throttle body cleaner; inexpensive and available at any place that sells auto parts. Throttle body cleaner is recommended rather than carburetor cleaner as it is less harsh, safe for throttle body coatings and is best for this task. Use cleaner, a rag and a toothbrush and or Q-Tips. Be gentle; don’t twist or pull on the pintle that protrudes from the IAC as it is fragile and you could damage it.

Thoroughly spray clean and flush where the IAC seats in the throttle body with the same spray cleaner

It is also a good idea to clean the entire throttle body itself, the butterfly valve inside of the throttle body and all associated linkage as long as you have things disassembled

 

i did that, but how do i know whether to replace it or not

 

Idles fine cold (when enriched), but not hot.

Do an intake smoke test to find the vacuum leak.

 

so im gessing its probably a vacuum leak and not the iac?

 

More than likely.

 

I'd hate to see you spend money you don't need to but I cleaned my IAC as clean as I could get it and ended up replacing it, which cured the erratic idle problems I was having. New plugs can't hurt. The general preference on plugs is Champion Copper or NGK.

 

hey guys any pics of this IAC? i want to make sure i dont pull the wrong thing.. thats what im doing today. preping the cherokee after 1 year of wifes abuse and maintenance

 

im having prob with my jeep bout the same as urs but i wait at a redlight and the jeep just turns off not sputtering or anything then tonight the temp gauge went from in the middle to low all the way low which is weird ..it did it while idling and driving

 

my jeep does kinda the same just shuuts off at redlight no sputtering and tonight the temp gauge went from in the middle to low then back to middle

 

my jeep turns off at redlight and temp gauge goes from middle to low then back

 

I picked up on your issue in the first post.