I have a 91 rs and I believe it has a 350 in it. First how can I tell the size of the engine. Second this just started to happen but when I push on the gas from either start off orfrom a low rpm stand my oil pressure drops to almost 10% but then goes to where it usually stays at alittle over 25%. What could be causing this???? Where should my oil pressure be at during idle????
Thanx for the support, Fred

 

Your oil pump is motor driven and its RPM is based off the RPM of the motor. It drops RPM when your car drops RPM (such as at idle). Anything above 20 psi should be good at idle.

 

the rule of thumb is 10 psi for every 1000 rpm, so at ide 10 psi is ok.your engine bearing may be worn out and it could be time for a rebuild.the only way to tell what the engine is by the casting numbers on the block.

 

Did the pressure drop suddenly? What weight oil are you running? As previously stated 20 psi + is normal, 10psi is low. Is it a factory electric guage if it is you might want to try a mechanical guage instead.