Okay so I have an 87 Jeep Cherokee that I bought for work.  It has 200+ on the engine.  It runs like a top but there is a problem.  It will just shut off every now and then.  If I let it sit for about 15-20 it will start right back up.  I have changed the fuel pump, filter, relays, ignition controll module, rotor, cap, plugs, wires and yet it still does it.  Any ideas of what it could be?  I'm pullin my hair out here.

Thanks folks

Heath
Heathnequent@hotmail.com  

by the way it's the 4.0 6cyl  

my neighbor is having the same problem on his early 2000s grand cheroke. he has even taken it to the dealership. we have replaced about the same things as you and even the tranny cooler and lines. somebody told him close pins on the the fuel lines. tried it. still happening. his motor is a 8cyl. what's going on????  

any body got any advise??????  

Sounds almost like vapor lock. Check the charcoal can, where the gas vapors go...it might be what's giving you trouble. Maybe go to a higher octane gas or add an octane booster. Did you go over your vacuum lines? My Wrangler ran funny because a valve cover vent had a small leak in it.  

Also, check your coolant sensor light..My 97 cherokee was doing the same..It would shut off in middle of town.  The check gauges/engine light would come on, while the temp guage would travel between cold and hot repeatidly.......Good Luck  

right on thanks for your help. if anybody has more info please let us know.  

My '97' sport does exactly the same thing, but only when the outside temp is hot and I'm in a stop and go traffic situation... It will just die, no check engine light or anything... I have noticed that it does it when my temp goes slightly above 210 (say 215 - 220)... Let it sit for 15-20 min, and it will start right back with no issues... I have thought maybe I have a bad temp sending unit and my engine is hotter than the gauge is telling me but it seems to act normal all other times...I've replaced most every relay and electronic sensor as well... I've done plugs, wires, dist cap, rotor button, TPS, CPS, NSS, all the relays in the under hood fuse box, both O2 sensors, complete new exhaust (cat, muffler, header)... I still have not figured it out... Some of the suggestions already posted seem viable... Although When I put on my new header, I also swapped to the 99+ intake manifold, so I went through all of my vaccume line connections then... I hope we figure something out... But my issue is so intermittent (5 - 10 times a year) you never know if the last thing you did repaired the issue... I'll keep digging...  

this really is no comparison to a jeep but my 07 Peterbilt will shut down when the coolant gets low, even though it only takes a half gallon to bring it back to full. It just had a loose hose that was leaking, over the course of a week it would get low enough to cause me a headache.

It could be a level sensor, they do corrode over time.