Alright, so I need some help please! I have a 2002 GMC sierra 1500 ecsb 4x4 with the 5.3L. It has a K and N intake, Poweraid throttle body spacer, It's straight piped with cats, and it is also nelson tuned. It has a major problem that I cannot figure out. I was driving down the road and went to pass a car and all of a sudden my Service Engine Light started flashing and I lost my top end and it has a bad ping in it at over 3700 rpm. I hooked it up to a scanner it has a random misfire code p0300. Cylinder 2 has the most misfires at over 570 misfires and the rest have either 2-8 misfires on the misfire history. I have done plugs (AC Delco Iridium Gapped to .40), I have done wires (AC Delco), I have done a fuel filter, and I did a de-carbonizing test. I have done an injector balance test and all the injectors went from 52psi to 42psi. All being the exact same. I have good fuel pressure at 56psi and does not drop. I am not losing coolant either. I have always ran 93 in the truck. I through some Lucas Fuel System Cleaner through it but that did not help. I am running out of ideas. Can someone help please? Thank You, Shawn Anthony