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

 

 

Yeah you need knock sensors to solve to P0327, it may solve the P0300 too. Make sure to RTV around the grommets to keep water out of the new ones. Also order AC Delco ones, and do the harness at the same time.