Injector (P0204) and Misfire (P0300) help needed; 2015 - L83 Engine (5.3L)

[89Suburban]

Problem has been solved. My plan was to replace the two injectors that were coding again. Being a DFI engine, the intake has to be removed to expose them. Last time I paid someone because of time constraints. This time I did it.

Got the manifold off in about 30min. The wiring harness that feeds the injector banks was at the rear of #8 (back left corner looking at truck). I started tracing the harness back and saw where it had been pinched by the transmission bell housing. Worked it loose, got enough slack to work with it, opened it up and saw where two wires were exposed from rubbing. Several strands were cut. Im guessing it was the edge of the firewall making intermittent contact. One was worse than the other.
Repaired them and reassembled everything. Did not replace #2 & #4 injector to ensure that was in fact the issue.
CEL turned itself off and no more codes in the last 100 miles. Truck is back to full power and purrs nicely.

Man what a headache!!!! Was so close to throwing a thermite in the engine compartment.

Excellent job tracking that down!

 

[Tahoe14]

Good find and good info that may help someone else that may be experiencing the same issue.

 

[Denise Kilgus]

Great info and having similar issue(s). Definitely worth a look at the wiring. Thanks!