I changed the sending unit recently with no change in the gage reading and tested my oil pressure with a gage on the block and the oil pressure is perfect. That leaves me to assume it's the gage or the wiring. I plan to remove the gage and wire it directly to the sending unit at the block. That should determine if it's the wiring.
We wouldn't love these cars if they functioned like some damn computer riddled modern car that nobody understands, not even the mechanics. I beg your pardon; they are now called service technicians for good reason.
Cheers,
Tom