Crank Position Sensor would be my guess as the culprit.
I had the same thing go wrong with my jeep at 150k.
In my situation, I didnt have a code, just the cutting in and out at any speed. Item runs for 80+ at autoparts store for my jeep. not sure if you have one on your jeep, but worth looking into. 20 min fix. make sure you have at least 2 feet worth of extensions and a swivel adapter. YOU WILL NEED IT unless your hands are smaller than an asian guy at 5'7" and a weight of 150. THAT asian guy would be me!!! so no one can say im talkin trash.
2001 Cherokee XJ Sport 4.0L
3" Rough Country Lift w/ Daystar 1.25" TC Drop Kit
Flowmaster Delta 40 Series
K&N Drop in Air Filter & Procomp 10" E-Fan
AirRaid TB spacer w/ 62mm Bored TB
BFG All-Terrain K.O. on Black ProComp 87's