Almost all 3rd Gen members report getting BETTER gas mileage after getting a tuner and disabling MDS...

 

you arent alone, there are many threads about this as im finding out doing some homework on here. I just purchased my vehicle last friday, i was at the 45 range and had a soft vibration in the gas pedal, would not be noticeable to a passenger however but was noticeable, at first i thought it was the speakers in the truck from the loud music..so i turned it down and still there. Did the tow haul mode thing and gone. With only 80 miles on the truck its a little concerning but i can live with it.