Hey guys, I have a 96 Tahoe 4x4 with the 5.7 Vortec. I recently noticed a significant knock coming from the motor and when I got underneath it, i can feel the knock coming from the oil pan. It is a solid, rhythmic knock, and it stays there under power and at idle. I am thinking it is a loose cap seal, or piston slap, but before I start tearing apart my daily driver, I would like a bit more certainty of what it might be. It is there at a cold start as well as when at operating temps. My oil pressure has dropped to about 10 psi, and will only peak at around 40 under WOT. I am also noticing a drop in rpm at times. Any help would be greatly appreciated.