2002 Silverado 5.3 - 160K miles. Issue – Started the truck today and the oil pressure was at 0…. Warning light came on saying low oil pressure. Shut it down… waited a second and restarted… pressure “caught” and went up to normal. Drove the truck as normal, but it oil pressure seemed to move around more than normal. Got home… Stated it back up.. same thing keep happening….0 and then I give it gas and it catches… goes up to 40-60psi. Someone told me a check a few things. 1.Change the oil filter….it could be collapsing. ( even though I just changed oil and filter a month ago) I got a new oil filter… will be changing as soon as the truck cools down some. 2. Something about a O ring on the plastic pickup tube?? Can someone explain this in detail? How to do it? Part number needed?