My ‘85 22R runs like a champ but, I just developed a problem with the oil light. My idle is set around 550RPM. Prior to today, engine cool and at idle, I’d get oil pressure around 15-20psi. Warm it would get a decent bit less. Warm and idling, my oil light would come on at times or flicker on and off. Any time it revved at all, the light would go off. Today, my RPM’s/pressure dropped, to a normal extent, and my oil light came on but, when it revved up, oil pressure built but the light didn’t go off. Let it cool down for a time, started it and the light was off until it warmed a bit and came to an idle, when the light came on and didn’t go back off. I know my pressure is good but, the oil light irritates me. Where do I start to look for the problem?

This morning, same kind of story. I let the rig cold idle and warm up as I was putting the trash cans on the curb. Drove to work and all was fine until I got into the parking lot. RPMs came down at one point, the oil light came on and didn't go off. Parked now. We'll see what happens on the drive home. Still no indication of any problem from the mechanical gauge. Maybe I just need to replace the pressure switch?

Thanks for any help you can provide.

Attached:
My oil sender setup with a stock pressure switch and line to my mechanical oil pressure gauge.

Oil pressure and light at idle.

And the oil pressure and and light when slightly revved.