I have a 6.5 Suburban 279K has a good wrench engine now, no idea when it was installed. runs poorly. A non qualifed show installed an injector pump, did not have the OBD1 scanner to set DTC. This was a year ago just borrowed a GMTD scanner, it has 3 codes 18 pump cam reference error, 35 injector pulse width error, and 54 PCM fuel circuit error. DTC is now is -0.65 Desired timing is10.9, Actual is 14. if you run it 5 minutes on a hot day and rev it up it will run good, with check engine light comes on.

Any ideas?? I won't go back to the shop that installed the pump, he can't fix 6.5's