Pinging

Something that I have run into on two different GM engines... check the EGR system. If the valve is not working or any of the EGR circuits are plugged, you get ping. This system puts exhaust gas into the intake charge to reduce NOx emissions, but the engine also needs more ignition advance to fire that charge. If no exhaust gas is getting into the cylinders, the engine management system really doesn't know that, and the engine pings. Check the EGR valve and the exhaust inlet circuit from the exhaust manifold (I don't think the EGR valve mounts directly in the exhaust manifold on that year 8.1 and is fed by a tube). If those are clear/working and the engine still pings, get an emissions test done. If NOx is high, then there might be a plugged EGR circuit in the intake manifold. You have to take the manifold off and clean the circuits by hand (a messy, but rewarding process once your engine runs properly again).

Again, this is only a possibility. Try the easy solutions, first. If they don't work, check the EGR valve. If it is not working, it should be easy to change on that engine and there are videos on YouTube that show how it is done.

Regards-

Thanks for all of the great input as always. Has anyone used SeaFoam for this type of situation? I know that it stabilizes the gas, but it also appears to clean the fuel system as well and was recommended by several friends.

The engine has a "ping" sensor that will(is supposed to) adjust your timing for different grades of gasoline if it senses detonation. Perhaps what you are hearing is not pinging or perhaps you have a bad sensor.
Hook your engine up to a Scan Gauge and check to see if there are any error codes that are stored in your engine control module.

Try a bottle of Lucas fuel treatment

May be time for a tune up also. New plugs and wires. Do the gas treatment, injection cleaner, plugs, wires, and maybe fuel filter.

I agree with Scott bad gas (most likely sitting to long in the fuel tank). This happened to me earlier in the year. I have the same engine in my RV. I have a 50 gallon fuel tank so I went to Walmart and bought 3 cans of Stabil $6.94 per can and that treats 16 gallons of fuel, X3= 48 gallons and it solved the problem for me. I also put in 48 gallons of 92 octane fuel!

Have you run fresh fuel though it?
A load of premium with a can of Stabil may do wonders for it. Also, Chevron with its "Techroline" does a good job of cleaning fuel systems. You might run a few load of that through it.

It could be a number of mechanical issues too.