I currently rebuilt my 3800 and all is fine only issue is oil pressure I followed the Chilton book procedures ,I purchased a tuned pcm from ZZP Performance with basic tune and the question is my oil pressure sending unit has 3 wires which or all getting good ground but no power on any 2 should I have power coming out of the pcm on those wires that connect to the unit or maybe issue with pcm just need to know if power should register with no oil pressure..

Does the engine make bad sounds?

Is the oil pressure sender new and from a reputable manufacturer?

I think one should be 5V reference, GND and signal return.