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Author Topic: 87 XJ 4.0 bad idle and stalling  (Read 899 times)

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Offline WagoneerXJ

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87 XJ 4.0 bad idle and stalling
« on: April 08, 2008, 03:45:07 PM »
So my XJ is runnin weird. 87 XJ Renix 4.0/Auto. When ya fire it up it runs fine for a couple minutes, then the idle bounces around, between 100 and 800. When it idles really low like that, sounds like I have a wild cam in it. Kinda like the timing is off, or it's missing.

 When I'm driving it, and pull up to a stop sign or to make a turn, if I don't put it in Neutral and keep my foot on the gas, it will stall. Other than that it runs fine above 1000 rpm, acceleration seems unaffected. Any ideas what the hell is goin on?

I cleaned and replaced the IAC, TPS and checked the plugs. No change :(

 I have a complete 89 XJ 4.0 to take parts from if I need them.
98 XJ Sport 2 Dr, 3", 33's and Bushwacker Flat Flares
87 XJ Wagoneer 5", Dana 44, 34" Swamper TSL's
97 TJ 5.2 Magnum V8 swap, 4" and 33" MTZ's- GF's Jeep
84 Mustang GT-Built 351W 5spd
97 XJ - 3.5", 31" BFG. 370,000 KMS and counting!

Offline rws

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Re: 87 XJ 4.0 bad idle and stalling
« Reply #1 on: April 09, 2008, 08:20:13 AM »
This really sounds like a TPS, if this is a high milage vehicle it proable needed replacing anyway.  Should be set with a DVOM and check the ground wire, sometimes a new one has to spliced in. 


Offline WagoneerXJ

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Re: 87 XJ 4.0 bad idle and stalling
« Reply #2 on: April 09, 2008, 11:30:03 AM »
This really sounds like a TPS, if this is a high milage vehicle it proable needed replacing anyway.  Should be set with a DVOM and check the ground wire, sometimes a new one has to spliced in. 



I replaced the tps with a spare one I had. No change  :(
98 XJ Sport 2 Dr, 3", 33's and Bushwacker Flat Flares
87 XJ Wagoneer 5", Dana 44, 34" Swamper TSL's
97 TJ 5.2 Magnum V8 swap, 4" and 33" MTZ's- GF's Jeep
84 Mustang GT-Built 351W 5spd
97 XJ - 3.5", 31" BFG. 370,000 KMS and counting!

Offline WagoneerXJ

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Re: 87 XJ 4.0 bad idle and stalling
« Reply #3 on: April 09, 2008, 06:38:06 PM »
Got it figured, was a vacuum line to the EGR
98 XJ Sport 2 Dr, 3", 33's and Bushwacker Flat Flares
87 XJ Wagoneer 5", Dana 44, 34" Swamper TSL's
97 TJ 5.2 Magnum V8 swap, 4" and 33" MTZ's- GF's Jeep
84 Mustang GT-Built 351W 5spd
97 XJ - 3.5", 31" BFG. 370,000 KMS and counting!