Gmc Denali 2024 Diesel Mpg. Does anyone have any real world data on the 2024 6.6 gas v/s 6.6 diesel fuel economy. We've only tested a sierra 2500hd denali with the diesel engine, which earned 17 mpg on the highway.

We’ve only tested a sierra 2500hd denali with the diesel engine, which earned 17 mpg on the highway. View detailed gas mileage data for the 2024 gmc sierra 2500hd.