I don't drive normal. My gas mileage sucked before the tune and is a hair better with the tune. Vehicle computer says my average for the last 13,000 miles is 18.1mpg. The Fuely Application, when I was using it, said my mileage was closer to 16.9mpg. I floor it a lot and get up to speed as quick as this beast can get there. I also remote start the vehicle in the winter a lot so that drops it and I live in the Northern half of the US where we get 'Winter' Gas for 6 months of the year, which lessens mileage. Before the tune I was clocking 17 on the car computer and 15.9 on the Fuely App.