I have a well maintained 97 extended cab V6 with the same oil pressure problem, though it started for me around 100K. I had a guy go completely through the lower end. He found nothing wrong, replaced some things anyway (sending unit, filter, pump, etc.) and I started using 20W-50 oil. Several hundred dollars later, the problem is till there. Save your money for now. I'm still searching for a solution to this one. That guy who got his engine replaced is a LUCKY man!