Man its comfy sitting up high in the Sierra. The first tank of gas is provided by GM, but I am glad I don’t have to foot the gas bill for a large pickup- any large pickup! Since both Lyndon and myself are mileage snobs, we would probably not opt for the optional 6.2 Liter EcoTec3 if given the choice. We would go 5.3. But we might not have a choice if we were towing the 9500 pounds behind us the vehicle allows. So GM uses Active Fuel Management.
Back in the day in 1981, GM offered the V8-6-4 in Cadillac in order to turn off cylinders to save gas when extra power was not needed. However, the system was rife with glitches and was quickly discontinued. Fast forward to today and GMC has perfected Active Fuel Management. The only clue to let you know whether the engine is running in four or eight cylinder mode is the fuel economy display screen in the instrument cluster.