Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
If you look at all those codes together, they seem to be indicating there is unmmetered air going into the engine. There have been reports of PCVs not sealing properly and warped valve covers wreaking havoc with air flow; so, if I were you, I'd start looking at those first, then move on to other areas where air might be coming in like the intake manifold, hoses, etc.
Let me know what you find.
Most of these checks are performed with a smoke machine; if you don't have access to that kind of tool, then you could use a mechanic's stethoscope to go around the valve cover. Other than that, you'd have to remove it and set it upon a flat work bench to check it.