I bought a 2000 Wrangler last week, 116,000 miles. It had a tendancy to die on me whenever the engine returned to idle. I didn't happen everytime, maybe 50% of the time. No check engine light. So, I did was what recommended on this board, cleaned the throttle body really well, replaced the IAC and the TPS. I started it up and the engine slowly climbed to 3000 rpm. I shut the engine off, restarted and it idled just like it was supposed too. I let it run for 10 minutes, didn't die. Later that evening, I drove around the neighborhood, stop and go, idled around, etc, didn't die. I thought I had the problem licked. Over my lunch today, I decided to take it to the court house and get the title figured out. About two blocks from my house, while stuck behind a very slow moving car, the jeep died. It was at idle, or at least very close to idle. It restarted and I drove it home. In front of the house, I put it in park, and it continued to run. I then stepped on the brake and pulled it into drive and it died. I didn't try to restart. The engine light came on when it died a couple of blocks from the house, but it then went out and has not come on again.
What's the next thing to check? Fuel pressure? Is there a sensor on the transmission that tells the computer what's going on there? Could it be bad? It does have a new Jasper transmission in it, perhaps could something be the problem with that which would make it die? MAP sensors, could that be part of the problem?
Is there a diagram that shows all of the vacuum lines that have anything to do with the engine running? What is the black box on the drivers side of the engine up against the edge of the hood? It has a couple of vac. lines coming from it. Where is the vacuum pump on this thing?
It could be the Crank Position Sensor (CPS). Symptoms of just dying without warning, then restarting OK, are common when the CPS acts up on the 4.0L. The CPS doesn't always throw a code.
(Eventually the CPS gives up completely and will not restart)
I replaced the CPS yesterday and I'm still having the same issues. Does anyone think it could be electrical? Would a bunk battery cause an engine shut off issue? The batter is only a couple of months old as the previous owner indicated before I bought the jeep from him. I also see that the PO shot what looks like silicon into the PCM connectors to keep moisture out. Is their any way to clean that stuff out and cover them with something else water resistant? I see that I can purchase those covers from eBay, but they want $30 a piece.