I have a 2004 grand cherokee lerado 4.7 liter v8 the other day the radiator went out so I baught a new one and replaced it I drove it around to make sure everything was good an all the sudden my oil pressure gauge dropped to 0 the jeep cut off an wouldent start back up waited awhile started it again an it starts right run an runs fine no knocks or ticks oil pressure reads fine after about 20 mins oil pressure drops to 0 jeep cuts off wait awhile starts right up then does it again what could this be ? I know if the oil pressure switch goes out the gauge will go nuts but would that cause it to cut off ? If it was the oil pump wouldent not have pressure the whole time not just after it run for awhile. ? It's throwing evap codes someone said knock sensor or crank sensor also I've changed the oil an filter an ran some seafoam in it any ideas on what could be going on with it ?

 

The switch also supplies info to the PCM. The switch is easily damaged by hamfisted oil monkeys when the remove the filter.