Sabarrow

I have an issue looking for some help. Have a 99 xj 4.0 been running great. Went to restart the other day and nothing no lights bells or anything tried to jump nothing. Pulled and checked all fuses went to jump again and before I could fired right up. clock was reset but other than that ran great. Drove to work in the morning no traffic no problem. Started fine leaving work, took longer due to traffic about 3 blocks from the house check gauge light came on and volts were pegged to 19. Got home fine parked it tried to restart nothing again. Went out the next morning and started just fine like nothing. Been reading a bad Crankshaft Position Sensor can do this when engine heats up. Also going to check all connections. Any help is appreciated.