Pontiac Repair: oil pressure gauge, oil pressure gauge, oil pressure sending unit

Question
1995 camaro lt1

hi there when starting my car the oil presure gauge read's 1/4 up to fisrt line after driving for about 30mins it'll drop to the red line on the bottom and the check engine light comes on when stopped, when i start going again it'll go back up to the same 1/4 line what could it be i a checked the oil it's fine.could it have something to do with the sending unit? also what if it's not that what else could be the problem?

thanks.

Answer
First, remember that an electrical gauge is not always accurate. The first thing you need to do is check the oil pressure with a mechanical gauge and compare it to the electric gauge. If the pressure stays OK on the mech. gauge, then you need an oil pressure sending unit. If the pressure drops off on both gauges, then you have an actual pressure problem that could be caused by alot of things like, bad pump, sticking relief valve, worn bearings, etc.