i am only running 8 MPG. i put a s&b cold air intake on my truck and a diamond eye exhaust and only pushing 8 mpg. I just got the truck as a hand me down in april but previously it sat for almost 8 years and before that my dad would use it as his heavy duty work truck. He kept up on oil changes and basic maintenance but never thought about adding performance. Might i add it pulled a 500 gal water tank lots of chemical all over the montana country side. I know for a fact it has leaking up pipes and at least one injector going. i haven't chiped it yet but in time i will. Is there anything i should look to buy to help increase the MPG.