TJ Engine Cutting Out

[Kenneth Patton]

Hi, this is my first post on your forum. Have owned Jeeps for 30 years, just now have joined a forum. Please excuse the looong post, I want to describe my problem in detail so maybe we can come up with a solution.

I have a 1999 Wrangler with the 4.0L engine, A/C, cruise, 5 speed, 65,000 miles. For the past few years, I have had a problem with it cutting out after driving 30 to 50 miles. It will start with a momentary "chug" then progressively get worse until the engine will die then immediately re-start. After a couple of these big cut-outs, it will be OK for another 10 to 20 miles then the pattern will start over. I first thought water in the gas, but have now decided it is ignition. The tach dips on each "chug" and goes to 0 on the big cut-outs. It has not left me on foot, yet. Just been very aggrivating. The problem shows up quicker in hot weather so I assume that an electronic module is getting hot and breaking down. Coolant temperature is a steady 210 year-round

I have changed plugs, plug wires, distributor cap and rotor. I am ready to start on the electronic modules in the ignition system but would like to get the most likely candidate first.

Any help and/or experiences would be appreciated. I think I have covered all of the details but please ask if I have left out an important detail. Thanks in advance for your help.

 

[SteelHeadz]

Is the check engine lamp on ?. Possibly something getting overheated that's shutting down an electrical component or module. If it was a fuel pump that's cutting out, I would assume that everything else would stay on exept the engine. Check under the hood and under the jeep on possible rub throughs land chaffed wires that maybe causing the shutdown. I've seen an O2 sensor wiring melt the insulation on the exaust pipe and intermittently shut down the engine when the signal circuit contacts the exaust pipe.

 

[Kenneth Patton]

One detail I forgot, the check engine light does NOT come on.

Is the check engine lamp on ?. Possibly something getting overheated that's shutting down an electrical component or module. If it was a fuel pump that's cutting out, I would assume that everything else would stay on exept the engine. Check under the hood and under the jeep on possible rub throughs land chaffed wires that maybe causing the shutdown. I've seen an O2 sensor wiring melt the insulation on the exaust pipe and intermittently shut down the engine when the signal circuit contacts the exaust pipe.

 

[Matt2001TJ]

Crankshaft sensor could be the cause. But,...does not change with weather. Good luck...MATT....

 

[ronnieb]

if it's an automatic check tork converter, just unplug it ,and go