Ok this is not in my vette thank god but in my 96' Z-71, I did some work on it replaced the oil pan seal, timing cover,timing chain and sprockets, intake manifold gasket, one fuel injector, and rear main seal. During this i broke the sending unit for the oil gauge, I bought a replacement from autozone and the pressure reads about 70psi at idle. I thought maybe it is the wrong unit so i got another from the dealer and samething 70 psi. I then drained the oil out of the pan and started the truck to where it dropped down to 0 psi just for a second or 2. I then put about 1 qt of oil in and it went back up to 70psi. The next step I guess is to get a gauge and hook it up to where the sending unit is screwed in and see if the actual pressure is 70psi. If anybody has ever had this happen or has any suggestions I would greatly appreciate it. Before i started working on my truck the normal pressure was 40psi.

Usually, when this happens to C5 owners, the problem is with the sender unit. In your case, I think you are on the right track by using a different gauge to test oil pressure. There's a chance your factory gauge is messed up and this will either prove or disprove that idea.

Good luck.

Dave

Perhaps one of the oil journals became blocked when you replaced the intake gasket. This would cause the pressure to build quickly even with just the single quart of oil you tried. If it turns out not to be the gauge or sending unit you may want to check the gasket placement. does it excessively protrude anywhere around the matting surfaces? hope you find it before the seals blow.

thanks for the responses, it turned out to be the gauge in the dash had lost its calibration. I hooked up a gauge to the engine and it read the correct pressure.
Thanks again