I am flashing a code 43 acording to the manual it's the "fuel system" I took off my fuel rail to replace the FPR with a B&M and after that I had the problem, could it be a bad fuel pump or filter or maybe clogged injectors? any input would help

 

Get a fuel pressure gauge, see where your pressure is set at. Most likely a bit too high.

 

fuel pressure set at 40 psi at idle and 50 psi at WOT is that too high? I turned it high for the NOS