It's the crank sensor!
Join Date: Nov 2007
Location: Central Minnesota
I think it is likely to be more of a problem with the oil pressure sending unit.
The sending unit is located directly above the oil filter. It can be jostled when you or a shop is changing the oil filter.
First thing to do is to check the connector leading to the sending unit. If it is okay, I'd recommend changing that sending unit. It is a very common fail. And if you do so, do yourself a favor and buy the replacement directly from Jeep for the best reliability/accuracy/mating with your factory gauge.
99 Cherokee, 4.0 AW4, NP242
Past Jeeps: 49 Willys, 81 Scrambler, 88 Comanche
Without "data", all you have is an opinion!