I have a 91FB 305TBI w/146000 miles. My oil pressure starts off at about 30-35 psi when idling, and will rise slightly with acceleration. After driving for a while and bringing the car to operating temp. my pressure dips to 20-25 and will reach 30 under acceleration. Oil is changed regularly. Is my pump going? Maybe a pressure test would help. Any ideas?

 

What you are experiencing is normal wear on the bearings and such. Pressure will decrease over time. So long as you keep up on the maintenance, you should be fine. GM says anything over 10psi at idle is ok.

Time to start collecting money for a rebuild though.

 

Of course your oil pressure drops once the car heats up. Once the oil gets warm it thins out a bit thus decreasing pressure.

What happens to the Crisco when you heat it up in the frying pan?

There's nothing wrong with your engine. Like ploegi says... wait until it's under 10psi... then your bearings are failing.


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1986 Trans Am
carbed 350 - .30 over with 9.75:1 comp.
+- 315hp/390ft lbs.
700-R4 with 2500 stall
3.27 (ick!) gear
SLP 1 3/4" headers w/MAC catback and cat.
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