Jay,

I would check the viscosity of the oil first. Try a drip test with oil from your engine and some new oil. Maybe some fuel (although I don't know how) got into the oil and reduced the viscosity.

I don't know how the oil pump or bearings could change to sudddenly cause low oil pressure. And its not the pressure release valve or the oil pressure wouldn't be good at high engine RPM. Not gage either or it wouldn't read normal pressure at high RPM.

P E H