07 5.3 LY5
Collapsed a lifter on cylinger 4 about 2 months ago. Replaced all the lifters and gaskets and since i first started it its had a really rough idle but is fine while driving. Has a flashing CEL while at idle but goes solid when given some rpm. Took it to the chevy dealer to have it diagnosed and they found that cyl 6 and 4 had bad/dirty injectors. Replaced all 8 and still have a misfire in cyl 6 and 2 now. Coils tested good miss didnt follow, injectors are the same plugs look fine other than 2 and 6 being a little lean but none of the fuel trims are super out of balance. Completely lost on this truck. Love it, really wish id have deleted it all from the beginning. Any help is greatly appreciated, cant find much info on anyone having the same problem.

 

Have you checked your actual fuel rail pressure and injector harness Low fuel pressure either from the pump or from a weak/defective pressure regulator can set this code . If I were a betting man since the issue is bank 2 specific check the injector harness for resistance and Continuity . Verify a Good clean ground for the Bank 2 harness all the way to the battery .Also check the Throttle body is CLEAN and well sealed , This can also set the 0300 code as well as the Mass Air Flow sensor . And it Can happen without setting the throttle body sensor codes . I know these things because I also Own an ‘07 Silverado