XJ Stalls For No Reason

97 XJ w/4.0 & AW4

Replaced the Crankshaft Position Sensor & The Neutral Safety Switch 2 weeks ago to fix a no start & an OD issue on this Jeep. Shortly after replacing both the Jeep will drive for several minutes and then just die while driving. No spit or sputter just instant death. Speed doesn't matter either. Whether 30mph or 70mph.

It restarts....sometimes immediately other times after just 3 or 4 minutes.

I am getting no CEL whatsoever.

Anyone have a clue?

You might try freshening your battery connections. I've read that our XJ's are very finicky about having solid, clean connections. How old is your battery? If you have a battery that is borderline it could be playing havoc with your electronics regarding engine management. You might also try checking your chassis or body grounds as they are notorious for failing.

Another idea that probably isn't your problem but might give you another item to check. When I bought my 98 it would periodically stall for no reason. It ended up being the lead wire in the console for the parking brake light. It had come loose and was grounding against the frame. This would cause a periodic stall with no warning or CEL. It always started right back up again.

Ignore the NSS, it has multiple functions but none of them will kill the engine.

You could have a failing ASD relay, synch sensor in the distributor, bad coil, harness problems, or the PCM.

Get it into a fault mode and check for spark, fuel pressure, and an injector pulse. You will need a fuel pressure gauge, a NOID light, and a spare spark plug.