Replace the engine with a remanufactured engine; then do systematic preventative maintenance going forward.
Unless like my 03 trailblazer it is an estimated oil pressure.
@Barkydog I know that the oil pressure gauges in the '47, '49, and '52 Dodges that my parents owned were mechanical gauges that had “0” and the left end of the scale, “40” in the middle of the scale and “80” at the high end. The oil pressure in these Dodges ran about 40 psi on the scale. The 1954 Buick my parents owned was a mechanical gauge but did not have markings for psi, but had “L” at one end of the scale and “H” at the other end. There was a white zone in the middle of the scale and for the 160,000 miles we owned that Buick, the oil pressure needle always rode at the top of the white zone.
I remember the old stove bolt splash lubricated 6 cylinder Chevrolet where the high end of the gauge was 30 psi. The gauge read about 15 psi when the car was moving and about 10 psi at idle.
