oil pressure dropping up and down in Tahoe

[ducknut]

recently purchased 95 Tahoe when idleing oil gauge shows about 20
then give it gas to go an drope down to 0 but no knocking and check
gauge light comes on but when I get to 30 mph it shoots up to 40 and
depending on speed it will stay from 40 to 60 but still dance a little.
When I come to a stop same thing will happen again. Replaced the pressure switch and did not fix it. I have heard that it could be the screen in the pump getting clogged can someone give me some direction to go. Oh the truck only has 114,000 miles on it. thanks

[SLJ2137694]

Put a mechanical gauge on it to see if it really is a pressure problem or an electrical problem.
I assume the oil level is correct?

[ducknut]

Thanks for replying. I put a standard pressure oil pump not a hi flow pump (mileage scared me)and a new screen and it is not dropping down to zero.
It stays about 10 to 20 at idle then when giving gas it directly goes up to 40
and stays at 35 or 40 while traveling along. It seems to react pretty quickly to acceleration and shifting even. FYI I was told 1.) to put a manual gauge to check it. 2.) replace the pressure switch. 3.) the actual aluminum housing that the oil filter mounts to also has a spring that can get weak so replace that assembly (dealer item), 4.) to replace pump and screen. had to drop the front part of the exhaust and take the motor mount loose to jack the motor up, take the guard off the flywheel area weasle the pan off. Thanks again.