I've had my new SD for19 days and im on my 4th tank but I got 15.5 on first 17.3 on 2nd and16.6 on my 3rd tank so far extremely pleased with the truck unbelievable power, really comfortable seats and I've never been in a truck this quiet had to turn the radio down and re beep the horn because I didnt hear it the first time while the radio was playing. I saw somewhere that this truck was quiter inside than a certain Lexus model . For some reason I am having a hard time getting factory molded mud flaps from my local dealer ,I am neurotic about all that dirt and mud splashing up on my brand new truck.