just drove 12hrs to visit a friend in aheville n.c. i ususally get 14mpg in the city so i figured the mileage should go up on the highway. NOPE i seemed to go through a tank pretty quick i was like wtf? so reset the tripometer and calculated after next fill up. i got 10mpg. im like how can it go down running on the highway? truck has new plugs wires cap rotor. new alignment which fixed the wondering steering wheel and no coast on a slight incline after a complete stop. just got 4 new tires. i did change wheels im running 245/75/16"s which measure to a 30 1/2 clutch is strong but im thinking the wheels may have changed the gear ratio a bit cause 5th gear is so gutless on the highway i had to drive the whole trip in 4th which made going up and down the hills in ky and nc a lot better. any suggestions would be helpful maybe i can a change of some sort before i head back to indiana on monday.