2024 Fuel Mileage 6.6 Duramax Diesel. Take a look at what has changed,. However, the average fuel mileage for 6.6 duramax diesel is set at 14 to 15 mpg.

Some owners of these duramax 6.6 turbo diesel engines have even hit near 20 mpg. Power retractable assist steps with perimeter lighting, $1500;