I have a 1991 1/2 ton 4x4 with 5.2L motor. I have had the truck for about three years. The truck has always had a problem when it comes to a stop. It runs just fine and then when it is a operating temp and you come to a stop sign the oil pressure drops. It has always done this. Recently the problem has grown worse. When the pressure drops the motor almost and sometimes does die. My question is, is this a clogged oil pump screen, bad sending unit, bad pump, or a combination of the three? Any help would be greatly appreciated.

 

You using the factory or an aftermarket gauge? My factory one failed to read pressure sometimes, even though it was running strong.
Anything over 15psi or so at idle is fine.

 

If the engine is idling low or dieing at a stop than this will cause a low oil pressure reading. Correct the idle issue first before testing the oil pressure at idle. The only way to check oil pressure correctly is to remove the sender from the engine and thread in a mechanical test gauge and take readings at the specified RPM in your serice manual.