The key to getting fuel milage out of these trucks is to keep your foot out of it! The way I understand it, a more powerfull truck dosen't has to work as hard to perform a given task, and will return better economy because it can just lope along, while the lesser engine would be running as hard as it could. I have never lost any milage with any of my mods, and have seen decent improvements when I can keep my foot out of it! Good luck

 

that makes sence i guess now that i think about it i do have a problem with a lead foot but its not that bad but yea i need a fuel pressure gauge and then the pules then injectors here we come tax time