2000 XJ 6 was running fine filled up gas drove home (9 mi) and it shuts off as if it ran out of gas,???, hit the key starts right up drive home. Figured bad gas. Starts doing this regularly, shuts off,stick it in neutral, starts up runs like normal. But now it's getting much more frequent, I've used half a tank with this issue recurring over and over. Any ideas?

 

First thing that comes to mind is thermal failure of the CPS. Kinda sounds like what was happening to me. Will it start in park? That is the one thing that makes me think not.

https://www.cherokeeforum.com/f2/cut...riving-241745/

 

CPS? The weird thing is when it's not screwing up it runs, starts ,drives like normal.

 

Mine would just stall, like you turned off the key, start right back up. Sometimes I could drive farther then other times. Towards the end it just got more frequent and harder to start. Why are you starting it in Neutral? Cause the vehicle is still rolling?

 

Exactly, yes I can catch it when it quits go to neutral, hit the key, go back into drive, keep going. What is the CPS?

 

Crankshaft Positioning Sensor.

 

The Crankshaft Position Sensor is a magnetic switch that senses metal passing close by itself, like the windows in the flexplate, and tells the PCM when to fire the spark plugs and shoot the injectors for proper timing and mixtures. If the signal from it fails for any reason, the PCM shuts the engine off. Over time, the magnet looses it's strength or the sensing coil won't send a signal because it got too hot or lost it's electrical continuity. Most of the time, the magnetic strength weakens and it just cuts out intermittently. This is one sensor that you should replace with OEM, as in Mopar, because it's construction and quality is important.

This sensor is mounted on the top of the transmission bellhousing underneath the steering column and behind the exhaust pipe.It's a Pain-in-the-*** to get to. It costs more than aftermarket ones for a reason. Quality!

Mopar! Do it once and done!

 

It's just a theory of mine - but I think that the reason for failure is *always* heat and not a question of the magnet losing strength. Perhaps other folks that drive manual Jeeps can jump in and confirm or refute my theory, but it seems to me that it's always the automatic transmission Jeeps that have CPS failures.
Between myself and my Dad, over 3 different manual Jeeps, we've driven over 700k miles without a single CPS failure.

 

You are very correct in that a critical electronic component is situated in one of the harshest areas of the engine compartment as far as temperature cycles go. The NSS gets it bad for the same reason (not quite as hot, but lots of extreme temp cycles due to sitting right on the trans fluid pan).

I know that when I have been wheeling, the trans tunnel inside, through the carpet can get very hot to the touch. I can only imagine the heat cycles that CPS is going through.