An oil pressure sending unit for that rig is $20. Change it, and go from there. We stock several. Just do it. OEM motocraft one is $20, an aftermarket one is $12.

Make sure to specify that it has a gauge, not just a light, they are different.

~Nate

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95 Honda Shadow ACE 1100.
1999 Plymouth Neon Expresso. 2.4 swap, 10.5 to 1 comp, big cams. Autocross time attack vehicle!
2012 Escape, 'hunter" (5 sp 4cyl)