If you check my first post on 7/4/13. You'll see that along with many others I was having problems where the 4.0L would just stop running. Not much to go on. pete1991YJ made a good case for the CrankShaft Position Sensor. Including how to get fault codes. #11 showed ignition fault. Replaced the CSP Sensor today and all seems well. It's an easy fix. Crawling under the jeep was the hardest part. One bolt on the bell housing and an electrical connector up near the firewall on top of the manifold.
(Some models have 2 bolts).
OH... by the way... the bolts are metric.
I've smiled before. But this time the engine actually seems to be running better. Especially at low speeds. Did many On-Off's. Started every time. Fingers crossed.