What would make oil gage and pressure keep fluxuating down before or after the oil pump has been changed on Pontiac Bonneville se and plugs and wires have been changed also keeps sounding check engine?

Answer 1

How many miles on this car? If it has high miles, it sounds like your main bearings are bad. This is not an easy fix. It involves dropping the oil pan to access the bottom of the piston rods. (That's where the bearing are.) Some cars are easier than others. I have not personally replaced them on a Bonneville, so I don't know how difficult it is on your particular model.

V-6 buicks have the oil pump, up to early 80 on the outside of the engine under the dist. the newer 3.1 3.8 3800 are in the same cover behind the harmonic damper.

A note to all when the pump is replaced, removed, or taken apart to check clearance the pump, both gear or g-rotor all must be packed with vasalien tell full then put backtogether. Forget to do it only this way, the pump will never never prime,,, before the battery goes dead from cranking wating to get oil pressure...so shall the rod and mains bearings die.