Intermittent low oil pressure

[Fless]

The fact that the OP hasn't been on here since the day of the original post should tell us to let sleeping dogs lie.

 

[nonickatall]

I wonder if you have some debris floating around in the pan and it will get stuck on the pickup screen and starve the pump. When you shut down the engine, it falls off and gets back into the pan - then repeat. Just a thought.

That's why i say: Remove the oil pan, check condition and swap oil-ring and relieve valve....

Cost 30$ for oilpan gasket, relief valve and o-ring. Brings knowledge if oil pan is full of debries, chips or mud. Shows if the O-ring is (part of) the problem.

Alternative is swap or rebuild the enginge, which is far more work and investment.