The idle in my '91' XJ has been fluctuating by 500 RPM when I'm stopped in gear (auto trans). If I put the truck in neutral the idle fluctuation disappears. The auto-trans shifts fine and I recently (within the last year) refilled the auto trans fluid 4 times (to get out as much of the old fluid as possible) w/synthetic auto-trans fluid. Am I looking at serious problems here?
'91' XJ: fluctuating idle when at stop, in gear
Mar 12, 2005
4 Replies
Doug did pass the time by typing:
Clean your throttle body.
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A little fluctuation is normal, it's caused by either the alternator or the AC compressor cycling.
Thanks Doug. I don't have to remove the throttle body to clean it do I?
Doug did pass the time by typing:
Nope. Not unless the idle stepper motor is well and truly clogged, then it's four torx screws to take the idle assembly off.
Just spray into the little slot and with the engine off, open the butterfly all the way and scrub it and the sides of the TB with a toothbrush and some cleaner.
All bolts/screws only go to a few inch.lbs so only use a driver on them, never a ratchet, and only tighten snug, like your putting a screw into soft metal (which you are). :)
Just remember if you do take the idle assembly off, do not pull the pintle out, that's a "bad thing". Also don't run the engine (or turn the engine on) with the stepper motor out and connected, the pintle will go flying.
That sounds like a dirty connection on the TPS. It has a connection to the tranny. The plug just gets dirty and can be cleaned with a spray contact cleaner. WD40 will work.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT'sDoug wrote:
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