1997 Jeep Cherokee Gremlins please help!

I have a 97 Grand Cherokee Limited 5.2 liter 2WD with 120,000 miles. First I’ll build the watch: Two years ago the car would die while idling, I changed the idle speed control valve and the problem went away for almost a year then started quitting again when idling. This time I installed a new “aftermarket” (NAPA) PCM, had the dealer flash the memory and was back in business for another year then the same problem, I installed another PCM and the problem went away for one week. The dealer again faulted the PCM. I insisted they keep the car find out and find out why it’s eating the computers, they had a mechanic drive it for two weeks and said its fine and they could find no other problems. It quit on the way home from the dealership. The diagnostic onboard never showed any faults, EVER. By the way, I installed a new battery in December and it died in January. The charging system appears normal with 14 volts while running, Coincidents? On a different note the chassis electrical computer would loose the date but not always the time when the old battery was trying to start the engine and even now intermittently says rear lamp failure when there all in working order. HELP!