heats up... sputters... dead

[MJ.rusty]

i have a 1990 comanche eliminator 4.0l 5 speed with roughly 150,000 miles. runs good besides it leaks some oil (what jeep doesnt). but here's the problem. when i drive it for about 45 min to an hour it will start to act up. it will cut out. come back in. cut out. come back in but my foot will still be on the throttle and the rpms will still be where they should be relative to my speed and gear. until i take it out of gear then it will turn all the way off. if i start it back up right away it the rpms will spike to 3 thousand. hold for a split sec. and come back to about 1. sputter a couple of times and then shut off again most of the time. sometimes it will idle fine for five to ten min. then i drive down the road a couple hundred feet and it will get pissy again. here is the weird thing. if i let it cool down for 15 to twenty min. turn it back on and go it will drive fine for another 45 min to and hour. now i'v checked fuses everytime just to make sure. and 2 times is was my trans fuse that blew. but every other time it hasnt been. i wiggle wires and all the good luck rituals i like to call them and nothing seems to help. i think it might be wiring or at least sensors. i have a new crank shaft sensor and throttle positioning sensor due to other problems. I'm starting to think it might be the ignition swith or something in the ignition system. or maybe the trans is over heating and trying to tell me something. or maybe even vacuum lines. but i don't know anymore. JUST won't TO WHEEL!

[Eagle]

Sounds a bit like what's been happening with mine recently. Something is getting "heat soaked," and doesn't like to run hot. Possibilities include the ignition module, the coil (which mounts on top of the ignition module), and maybe the fuel pump ballast resistor. Most folks tell me the ballast resistor isn't a candidate, that they either work or they don't work, but the symptomes with mine when it dies are like running out of gas. Problem is, since I started carrying a jumper wire for the next time as a test ... it hasn't happened.

 

With yours, next time it dies check your fuel rail to see if you have fuel pressure. If not, jumper the two wires on the ballast resistor and see if it'll run. If that doesn't work, look at the coil and ignition module.

[MJ.rusty]

yea ill have to try that next time. might be a little while before i get a chance to drive her. but thanks alot. and keep me updated on what you might find out about your problem.

[MJ.rusty]

i have no clue what it could be now. i have replaced the ballast, coil, and module all on seperate occations. keeps having the same problem. I'm thinking fuel pump.

 

and I'm looking for wiring harnesses too. can't find any. got any ideas

[mjdoa]

I had a similar,not exact problem.

The hotter it got the worse it ran.

Cool was cool.Hot was bad,sputter on acceleration,

stalling.

Replaced the fuel pump and sock(had to clean the

crud from the tank too),problem solved.

[Kenosha Warrior]

Yeah, my XJ always did this. The pump was getting cranky and after about an hr of highway/city cruizin' it would run like Id forgot to feed it.

 

sold it before I ever figured out the problem

[Tomahawked]

Fuel filter will also give same problem. If too much moisture is caught in the filter it will totally restrict flow. Just another possibility.