I have a 2013 Laramie Longhorn with 5.7L, 6spd, 3.55. I get 14.5 MPG in the winter, 16.5 MPG Summer. I drive 35 miles one way to work driving 62ish and 3 stop signs. If I pay attention to nothing else as I drive, I can MAYBE? get 16.8 MPG out of it. Any ideas as to what is going on? I should be getting 20ish from what I hear... Runs great and has plenty of power. Been this way since I got it 2 years ago....