I have a 2004 Silverado 2500 HD Crew Cab 6.0. I am getting the codes P0172 P0175 and P0300. Basically running rich on banks 1 and 2 and random misfire. The following has been replaced and still having the problem, Battery, Coils, Injectors, plugs, wires, throttle body and mass fuel sensor I have taken it to two local shops who have been unable to diagnose the problem. I have since taken it to the Chevy dealership they have had the truck for two days and can't figure out what the problem is. Has anyone else had this problem? Any other suggestions on what it could be?

 

I'd say ecm, but since you have it at the dealership , have them fix it.