I have a 02 Silverado changed motors from original. New motor was fly by wire from 03 or 04. Changed intake out for original. Have misfire code. Changed injectors can sensor new intake gaskets. Holding 50 lbs fuel pressure, no change spraying around intake ports with motor running. Have vids and pics of live readings from scanner. Only issue I see is 02 s1 b1 staying steady voltage which I know should vary can this be my whole entire multiple misfire problem. Changed maf sensor ran great. Until the next day when I started it. Sounds like I’m running in 5 cylinders

 

Put on a good set of non-conductive gloves or a spark plug puller and see what occurs.