I am at a loss. 2014 chevy 1500 5.3. Codes P0300 P075 P0157 and P0219A. I have changed plugs wires coils Injectors did the AFM delete with new cam and lifters. Turned AFM/DOD off with HPtuners. I have verified it is off. Still throws the same codes. Compression is 125 to 135 in all 8 Cyl fuel pressure is 50. What am I missing? Help please.

 

I am not all that familiar with AFM motors, but even so, 125 to 135 PSI is pretty low compression. In a non-AFM gasoline engine compression ratio 150 to 175 is normal, as is a fuel pressures of 55-to 62 PSI for the injectors to operate properly. In a normal engine you don't want more then 15% difference compression between the cylinders.