I am getting all 3 of these codes and truck is running like crap. Already changed MAF sensor today and code came right back so I put old one back in and still doing same thing. Got worse over the weekend when the cooler weather started. Like in low 70s during evening and night. When I changed the MAF sensor I cleared all codes and all 3 of those came back within 5 mins. I'm going to change knock sensors and intake gaskets and see if that helps with the knock sensor code. And then I'll go from there. Already checked to make sure MAF sensor was getting 12 volts from harness and it is so Ik it's getting power. I'm not sure what else to do. Very low power and a lot of hesitation and check engine light flashes often. I try not to drive it a lot so I don't mess up the cats bc of the blinking engine light

 

 

What are you working on??? Kinda figure a silverado, but what year and engine??

 

2007 Silverado classic with the L33 all aluminum 5.3L

 

Suspect a chaffed harness for the knock sensor code, need find a wiring diagram, may be a common ground or something between em....

 

Chaffed harness?

 

Knock sensor harness, under intake, rubbed through or chaffed....

 

I changed the knock sensors and intake gaskets. Still missing on bank 1 bad. I'm doing a exhaust back pressure test today to see if the cat is plugged which would be why bank 1 is missing. All the harnesses look good around engine. Even pulled off driver side valve cover yesterday just to make sure all the valves were moving like they were supposed to and looked for some broken valve springs just in case . Everything looks good. Runs great at idle and revs up fine when not in gear. Once in gear bogs down and starts missing right above idle. Other then that I still need to check fuel pressure but to me if it was that then both banks would be missing instead of bank 1 with cylinders 1,3,5,7 in the count. Anybody else think it would be a clogged cat?

 

Yeah seen that before too...