My car: 94 RX7 engine, drive train and suspension was placed into a Lotus 7 replica I call the Lotary 7 in 1998. Engine rebuilt, street ported and Garret single ball bearing turbo was installed with custom manifold four years ago.
Problem: Months ago oil pressure would start only 20 psi then jump to 60 or so after driving a bit. I assumed gage problems. Then recently no pressure! I put a test mechanical gage on the sensor port and it was truly only 1 or 2 pounds. I assumed pressure regulator valve as I had that spring go weak ten years ago. Took pan off and both pressure valves were fine. So after talking to friends I am guessing it is the oil pump O ring. See here


https://www.mazdatrix.com/faq/oring.htm
I hear that some rebuild kits did not have the right O ring. I am looking for your opinions before I get into this big job-- and I want to make sure I fix the right thing!

 

the front cover o-ring would be my guess.