hoorders

Hey everyone, I know there are lots of threads on this but wanted some thoughts on this. My truck is a 2002 Sierra 1500HD with the 6.0 gas motor. Im getting the P0300 randon misfire code ad the knock sensor code(cant remember the code number for that). Truck just had the following done: New Knock Sensors (did this twice with brand new sensors each time) and knock sensor wire harness. New plugs, wires, coils, fuel filter, fuel pressure regulator and new upgraded intake manifold gasket. Cleaned MAF. There are no vacuum leaks. Everything was torqued to specs. Im still getting the same codes after all of that. The truck runs absolutly perfect. So after all that, the same codes are still coming up. If it wasnt running well, I would continue to investigate the issue however, Im thinking of just ignoring my engine light on and leaving it all alone. Thoughts? Anyone ben through this and actually found the culprit to these annoying codes that dont seem to affect how the engine runs? Thanks in advance.

Tihs is probably a silly question, but I recently replaced my intake manifld gasket on my 6.0 and the set came with this other smaller gasket,,,,kinda oval shaped with 2 holes for mounting. What is that???? I cant see anything on my truck where that gasket would fit. Thanks

Definately has not always been like this....................my 2000 Z71 5.3 has a factory block heater and the cord end is just a black 3 prong plug.....the thermastat B.S in there.....it works no matter what the temp is outside.......