In Park we are fine right at 700-750 RPMs

In Drive at a light or even stoped it lobes from like 250 to 750 RPMs but still runs like a top ???

Can I adjust a air mixture screw or idle screw is there a such thing?

It's an 89 with 161k and new plus, wires, cap and rotor yeah all tuned up but this takes place still ???

Thanks Guys in Advanced

Have you tried cleaning your throttle body up? Have someone test your TPS and IAC. Most small shop mechanics will run a test for free. First clean the throttle body and see how that works.

once it warms up might need to do this to the families WJ as in first it idles low to the point it stalls out sometimes

I'll trying cleaning the hell out of the TB, if not this is where I suck as a Tech lolololol

Try this.........

The two absolute primary suspects for idle issues on your vintage are the idle air control AND the throttle position sensor. Resolves 99% of all idle issues. And get that throttle body clean!
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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

tjwalker Thank You

That's a complete answer PERIOD

Again Thanks

Trying this evening

I see that you are from Lake Havasu City.

LOVE that area. We used to take some uber fast powerboats out on Lake Havasu and had a great time.........Gotta love Copper Canyon parties! Wildest I have EVER experienced!

Good luck and let us know if cleaning the IAC and TB helps!

2 cans and TB is spotless but still runs from 250 to 750 in Drive and 700 to 750 rpm in Park.

I unpluged the IAC and nothing changed still ran the same so can Autozone or Checker check the IAC for me ?? Or just pay the 80 bucks ??? I hate not knowing is all ... If not that then the TBS is another 40-50 I'm sure ...

Thanks for any feedback ....

See if there is a mechanic who will check them. Most auto parts stores can not but they may have a meter you can borrow and check it in the parking lot.

Great post on cleaning the IAC.... what about the TPS? What needs to be done to check that it is operating properly?

TJ I'm not from HAVASU !!!! These people are NUTS ... BUT yeah Party's in Havasu are out of control hahahahahaha gotta love boo's and naked chicks ... I'm not a drinker due to training all the time hence my screen name lololol Used to train all the time now I'm cheating to Slow WHEELING with my new Red 89. Since my F150 with a bent beams needs new coilovers (that cost almost what I paid for my 89 lololololol).....

I'm going to have them both (IAC and TBS) checked tomorrow and go from there .... I will figure this out ...

Recleaned the IAC and set fuel pressures again I believe 33 psi and 42 psi under a load... It runs Great but does that sound like the right FIX ???

I mean it runs better and no more lobing in gear....