Based on my experiences, Tordne is absolutely correct, the M6 DFCO settings control fuel cut while shifting gears and the clutch is depressed. I use some fairly agressive settings with my 01 Corvette, so they are available on US-built vehicles. As for popping being caused by fuel entering the converters, I don't see how that can happen if you cut the fuel. I don't notice any popping when I back off the throttle. As for running the mixture so rich that it can't burn-- that's a good way to kill the converters.