After some mild (not much more than 5K rpm) romping on my 88 GTA (5.7), the oil pressure, at operating temp doesn't go above 25lbs, and reads zero at idle.

I pulled off a valve cover and started the car at full operating temp, had zero oil pressure on the gauge. The rocker arms on the back two had only minor flow, but the front two cylinders had good flow (would squirt well onto the inner fender).

The engine sounds normal with no unusual noises

2 questions

1. I'm thinking main bearing, are you?
2. I read in my manual that it is recommended to pull the engine and tranny together, would you?

 

change the filter and oil pressure sending unit. if that doesn't work, just change the oil pump. And no it's not a main bearing, it would make a lot of noise

 

If you have oil pressure at the top end of the engine then it sounds like a bad oil pressure sensor, check it out.

 

Ryan,

Thanks for suggesting putting a mechanical gauge in replace of the factory unit.

The mechanical gauge read 60lbs, so I replace the sending unit and the factory gauge works great.

You saved me a huge headache, not to mention the $.

Thanks again, Mark.