The first thing that you can do to ensure that your getting the best gas mileage is go over the vehicle to ensure that everything is working properly. After wards, if you want, you can remove your emitions, all that you really need is a pcv valve and a breather. But before doing that try switching your fluids to synthetics, wich will reduce the friction of your parts, less heat means longer life, less wear and tear, better performance which gets you better gas mileage. Also check the air pressure in your tires, if the pressure is uneven it will affect your gas mileage as well as your handling characteristic(yes they exist even though its a truck and most people dont think about how a truck handles). When your done with that, make sure that your not carrying excess weight, and wash off your vehicle. Its just simple aerodynamics air flows more easily over smooth surfaces than rough surfaces like dirt.
