Check all grounds.
Mine was having all kinds of problems: instrument cluster very erratic, windows spontaneously going down, VIC resetting.
There's a ground connection on top of/next to the alternator that was loose.
Not completely sure it's cured, but very hopeful.
This is on a 96 ZJ, 5.2L.
There are also 2 grounds from the battery: one to engine block one to fender.
(For what it's worth, I believe the loose ground I had was causing the PCM to overcook the alternator, resulting in (intermittent) voltages as high as 20 volts. I really wish the voltage regulator wasn't built into the PCM.)