Oil Pressure Warning with good oil Pressure on PP Gauge
Hello im a new member here, first post sorry it is long.
Backstory of Car(skip if you want): A month ago i bought a salvage auction base mustang gt from the dead that floated down a muddy river and i converted it to premium & performance pack specs. After rebuilding and draining all muddy water(it was everywhere, in everything) the car starts very easily after a new starter, new everything and after ran and drove ok. Engine was full of water, amazing how much but sadly it sat like this in auction yard for 2-3 months, bottom end was all water. After a month of fluid changes and electronic harness swaps i am getting P0300 p0300PD code. Replaced every bit of the electronics so far except any sensors/pumps mounted on engine, radiator, alternator, ABS unit, engine harness. Besides that every bit of the car has been replaced. I have not given the computer enough time to learn the crank position because i am afraid to run it too long with below glaring issue and its not legal to drive yet. I have done cold compression tests and #6 was showing low. With the amount of liquids in all the wrong places i was hoping it might correct itself magically later on down the road...going to do a hot compression test and leak down eventually once i sort oil pressure. I babied this thing, dried it carefully hand cranked to work it slowly and did not rush anything engine related but the fluids are still contaminated severely and will be changed again soon. I can go on really, escaped oil in exhaust makes quite a bit of white smoke as well. Flood cars are a mother.
Finally my Question: My cluster reads low oil pressure warning but the performance pack gauges i have are reading between 25psi(warm)-50psi(start) at idle. I'm in texas so its hot as all hell as usual so the oil is not cold.
How am i getting low oil pressure on cluster but pp gauges are fine?
Here are my Guesses:
1) I had a base model and the oil pressure sending unit in PP mustangs is different?
2) Oil Pressure Sending Unit is bad, but why am i still getting good reading from pp Guage tho?
3) Bad Oil pump?
4) Contamination or blocked oil passageways
5) Cylinder #6 is piston ring is leaking badly and i'm boned.(might be related, need to test)