Remove the wire from the oil pressure sender and measure between the wire and the engine block. It should read 5vdc, if not you got a bad regulator, if Ok then gauge or sender is not accurate.
Most modern cars use some type of Variable valve timing (VVT) Rhodes lifters are
in effect VVT. With so many people reporting hydraulic lifter problems (China) why
not a USA product that actually works.
Too many so called hot rod gurus have over cammed mean sounding (idle) to
show at cruise...