While the engine is warmed up and at a stop light or just in gear sitting the oil pressure gauge bounces from 20psi to just above the red line. IF i have to replace the oil pump which brand and volume should i get and the best way to switch it out, while the engine is still in the car.

Note to mention- the car has 180,ooo miles on it, there are no engine noises and the valve train in getting oil, plus i checked for metal shavings in the oil pan when doin oil changes which there isn't any, i use to run 5w-30 then went to 10w-30 which helps a lil when at idle and sitting at a light. Also i performed a compression check 190 psi to 188 psi in each cylinder I did a dyno pull after the transmission was installed also while i still had the 2.73 in the rear it pulled 290 at the rear wheel and 300 ft of torque I was shocked and so what the guy the tuned it.



The pic )above) is at idle/ the pic (below) at cruising speed at 100mph the oil pressure never goes above 40 psi

 

when its ldling are u hearing any knocking or clicking?

 

no noises at all i can hear the injectors pulsating and the vaccum of the intake

 

what yr? it may be the oil gage pressure sensor. should be behind the intake screwed into the block.
http://shbox.com/1/oil_pressure_sensor.jpg

 

its a 94 LT1

 

That is probably your oil filter getting sludged up. I noticed mine raises a little with a 5/30 oil change and ACdelco pf454 filter.

 

i would change the oil pressure sensor. with a 94 u may have one or two sensors, in both cases the sensor for the pressure gage is behind the intake manifold in the same picture in the link. and yes if u have a fram blacktop filter change to a different kind.

 

It's the cheapo FRAM orange filters that are the bad ones. Their gray (TG) filters are good, even though they also have a black top (or bottom once it's hanging on the engine).

 

I don't deal with fram oil filter it cardboard inside, i buy the pf454 ACdelco filters, I have a crate full of new ones and the filter is fine, i cut them apart after each oil change to see whats caught in the filter most of the time just lil black spots which arn't magnetic the spots are from the oil breaking down, i resently just baught a new oil sending unit, and my LT1 has it pressure sending unit on the back side of the intake manifold.

 

could be your oil pick up came loose