TJ 4.0 Stumble? - Page 4 -
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Unread 07-30-2013, 06:28 AM   #46
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2005 TJ Wrangler 
Join Date: Jan 2012
Location: Flint, Michigan
Posts: 86
I just replaced 02 sensor with no code and hasn't stumbled since

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Unread 06-09-2014, 06:54 PM   #47
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1999 TJ Wrangler 
Join Date: May 2011
Location: Manitowoc, WI
Posts: 90

Similar symptoms, it stutters on the highway or under heavy load. It has been steadily getting worse over the last few weeks, and now has gotten to the point I cant drive it to work. One new symptom is a P1391 trouble code.

So far I changed the CKP sensor and tested the TPS. New cap and rotor.

I pulled the Ignition pickup off the distributor and when I bend/roll the wires it sounds like they may be cracked, possible from heat? I am replacing the Pickup under warranty tomorrow.

also when I was looking around today, I noticed the ECM was pretty warm. I just got back from a 20 min highway ride from work but the ECM seemed exceptionally hot. Should I be concerned about this?
1999 Wrangler TJ 4.0 5spd -- 6" LA , 35" MTZ's , Ford 8.8 , 4.88 gears , SYE , Tom woods CV shaft
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Unread 06-12-2014, 04:48 AM   #48
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Join Date: Feb 2008
Location: Berryville Virginia
Posts: 117
Just a heads up, I had a 98 Cherokee with similar issues. Changed the front O2 sensor and fixed it.
Bville-Bud is offline   Reply With Quote Quick reply to this message

4.0 , missfire , o2 sensor , stumble , surge

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