How can I improve the fuel mileage on my new 2013 Dodge truck with the 5.7 Hemi Engine

...well you might be mindful of needless accelerations....so the guy behind you gets a little testy...big deal...you don't have to impress anyone with your rapid acceleration...if not haulin' take the economy car instead~

best way to get better fuel milage put a cold air intake on and a good cat back system it does help and gives you some more power

get a diablo trinity along with intake and exhaust it gives you better mileage I have one being hard on the gas i get 13.9 mpg

I have a 2013 RAM 1500 Quad-Cab 4x4. I average around town about 16-17 MPG. On long haul trips with cruise on I get about 17-17.5 MPG, without cruise on I Avg. about 18.5-19 MPG. The newer 2015-2016 1500's offer better MPG, but you lose some of the horsepower of the "HEMI." Sure wish they'd have not cut corners with the "HEMI" edition. I wouldn't mind the MPG if it were a true HEMI (426 cu. in.).

ummm I'd say a fuel cell tank.its expensive but probably best offer. Cold air intake and plenum gasket. Maybe better catalytic converter and exhaust.