So as the title says I am having issues with the idle on my 2000 sport, with the 4.0L.

It starts fine runs well and drives normal. But after the engine is warm and has been run for any distance, when I stop at say a light the idle drops really low. Then amps fall, and my oil pressure follows. (I am thinking due to the low rpm's) Though when I touch the gas everything snaps back to normal, and off we go.

It never stalls just drops to a few hundred rpm. Any ideas?

And I used the search, just didn't find anything that matched up. Thanks

 

I would start by cleaning the throttle body. It is easy to remove. Pay close attention to the idle air control. Make sure the "plunger" and the housing are clean.

 

The Idle Air Control (IAC) is mounted on the back of the throttle body. 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

Reinstall IAC and check idle quality

 

Thank you for the help. I will give this a shot this weekend. Thanks again

 

Worked great, she purrs like an old cat again! Thanks for the help!!