ETurp

2001 Jeep Cherokee inline 6 4.0L
got this as my first car so I’m a bit of a newbie. Trying my best
Got this car with check engine, light on, so I took it to my buddy, he’s a mechanic, to scan the codes to see why it’s on. Said I had an evap leak (hose from charcoal box) and not firing on cylinder 6. He told me to buy a coil pack so I bought an “MSD ignition blaster coil pack” and six new Champion OEM replacement spark plugs. Installed about five days ago and ran noticeably better for a few days until yesterday when I took my car out and once it got to operating temperature and I slowed down or came to a stop the car would turn off. Then I’d have to put it back in park and turn it over again. It starts right back up and idles too, but once it warms up it shuts off coming to a stop or slowing down too much. Any clues if it might be related to coil pack being defective? Help very much appreciated.

tech

If it is not misfiring I would say the coil pack is ok , for a stalling problem I would look at maybe cleaning the throttle body and idle control motor and if it still stalls change the idle control motor .

ETurp

Probably a dumb question but how would I go about cleaning the the throttle body? Can of brake clean and a rag?

cruiser54

CRUISER'S MOSTLY RENIX TIPS

THROTTLE BODY AND IAC CLEANING

OCTOBER 30, 2015 SALAD 26 COMMENTS EDIT
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.

Revised 1-31-2016