Gonna explain some fixes before I put this posting to bed. When I put in the new cam, I also changed the oil pump. Here is where I made 3 vital mistakes. 1; I put the correct o-ring into the oil pump cavity before installing the pick-up tube. When trying to put the tube into the pump, it wouldn't fit. So, I used the smaller o-ring. The tube fit, and I secured the tube to the engine. 2: I didn't pay attention to the tube, in that it has a retention groove for the o-ring. 3; I discounted the low oil pressure reading on the gauge as just a faulty instrument.
Early in this posting I had mentioned that I had 2 DTC codes relating to the knock sensors. Thinking it was an octane rating too low for the PCM timing, I added a bottle of octane booster to see if that was the cause of the DTC'S. Road tested to duplicate the problem. When I got off the highway, there was a very discernable tapping. A lifter had collapsed or failed all together, and the MIL re-illuminated. Hmmm...
Lifted the engine off its' mounts, pulled the oilpan, undid the 2 8mm nuts that hold the pick-up tube to the windage tray, undid the 6mm screw that secures the tube to the pump, and the tube literally fell out of the pump. So did the o-ring I put in the pump cavity. All along, the pump was sucking air, the gauge was correct with the low pressure reading, and the knock sensors were just doing their job telling me that, indeed, there was noise they were hearing (lifters pumping down). At this point, I noticed the o-ring groove in the tube, put on the correct o-ring in the groove, then fit the tube back into the pump with a little effort, put the pan back on, reattached the engine to its' mounts, and fired it up. WOW! Instant oil pressure ( almost 60psi). Took the truck back to where the codes would set, only this time NO DTC'S, and the engine seems so much stronger!
I guess we're never too old to realize our mistakes, and make the needed fixes. Live and learn. Anyways, that's my story and I'm sticking with it! I'm glad I made the change. The truck is so much more pleasurable to drive