Need help diagnosing engine/sensor problem

I've done a lot of reading and a lot of searching but I'm still not 100% on what my problem is.

My Jeep-1995 Cherokee Sport w/ HO 4.0L, AX15, NP231 etc.

Symptoms:
After starting up the truck and driving for a while (has happened anywhere from 5 mins into drive all the way to 40 mins into drive) the tach drops to zero and the engine dies. If I have enough RPM and enough momentum the truck restarts itself. If it dies at low RPM's and I come to a stop the truck will not restart right away. I have to cycle the key several times to get it to go. The truck will crank but not fire immediately.

It has happened with truck cold & hot, high & low RPM's, high & low speeds, raining and dry out. I don't want to throw any miscellaneous info out there but the first time it occured was after I installed cruise control on the truck.

Hypothesis:
I was thinking CKPS (crank position sensor), but I read somewhere the CKPS is used only on start up, and after that the ECM ignores it. So now I'm wondering if the Cam Position Sensor (CPS) is intermittently going out. A couple guys mentioned TPS, but I do not see how this has any bearing on the issue.

I don't have a check engine light. I have not tried to pull codes, but I will. It is OBD I, so Advance Auto can help with that for free. I wanted to get a good idea of what the problem might be before I headed out and tested the crap out of everything.

Thanks for any help, ya'll!

Regards,
Nick

The codes will be a big help

I have had a similar problem with my RENIX - try this:

Visually check the CPS wiring from the sensor to the engine bay harness, paying particular attention to the section closest to the exhaust header. When I had that sort of problem, it was caused by the harness having rested against the manifold and melting through to the point were it was possible for both wires to directly contact the manifold - thus losing the CKP signal and thence both ignition and fuel injection. If the vibrations were right (they usually were - this was a royal PITA to troubleshoot!) the engine would still be turning, the CKP harness would break contact with the header, and the engine would start itself back up!

The fix? I didn't need a new sensor, I just cut the melted wiring, spliced in a new section of 18/2 SJOOW, and reterminated. I left it long enough to go through a bracket on the firewall (which I put in - just a zip-tie base and a loose tie, really...) to ensure that it wouldn't happen again.

That was about 75Kmiles ago...

5-90