Newbie here needing help. I have a 2004 5.3L (L59)1500 4X4 Suburban with 144k with no oil pressure at all. It began as a lifter tap at rpm's of 2300 and above, no noise at all below 2300 rpm's. It had plenty of power and had no vibrations at all while driving or reving the engine up at idol, oil is changed around 3k-5k miles. My oil pressure was fine (factory gauge on dash) and would increase as the rpm's went up. I drove it the other day when going on a hr long trip and when i got there my oil pressure was low, warning did not come on. The truck sat for about an hour before i started it back up and had no pressure at all and warning light was on. I let it run for a few min to see if the pressure would go back up but never happened. I shut it off shortly after the engine started to make noise. I pulled the valve cover on the passenger side(side that had the lifter tap at 2300 rpm's) and it was clean and dry, no oil getting up. Could this be the seal in the pick up tube or bad oil pump? My fear is worn bearings. The engine does not burn a drop of oil between oil changes. Thanks in advance for any help with this.