Derrick Mitchell

Ive been working on my 96 jeep Cherokee ever since it threw a code saying it had a bad map sensor so i replace the map sensor cleared the code and it runs great when i first start it but after it gets warm it idles low and when i start to come to a stop it idles lower but when i stop the rpms come back up. donno what to replace and i already cleaned my IAC. It also revs up and down some times when driving

cruiser54

Ever cleaned the throttle body?

Derrick Mitchell

no not yet but will hopfuly it helps

cruiser54

Originally by TJWalker of CherokeeForum & JeepForum



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 retracted, the air control passage flows more air which raises the idle speed. When the valve plunger is extended, 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. This should be part of a normal tune-up procedure and whenever idle/stalling issues are present.

CLEANING THE JEEP 4.0 IDLE AIR CONTROL

1. 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). On ’91 and later, it may be easier to just remove the whole throttle body. Be sure to use a new throttle body to manifold gasket when reinstalling.
2. “Gently” wiggle out the IAC from the throttle body. Gasket/O-ring on the IAC can be re-used if it is not damaged
3. 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 oxygen sensors. 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.
4. Thoroughly spray clean and flush where the IAC seats in the throttle body with the same spray cleaner.
5. It is also a good idea to clean the entire throttle body bore itself, the butterfly valve inside of the throttle body and it’s edges, and all associated linkage as long as you have things disassembled.

Derrick Mitchell

So im still having the rpm jump while going down the road and i have replaced the tps,iac, map sensor ,and the pcv valve cause i broke it taking it off but i am thinking it might be either my o2 sensor or my CPS. Also can seafoam mess up your o2 sensors