Hey kevin have your reset the computer yet??? the first couple years I had the truck it was getting like 13-14... I know I don't run it like i used to but I still stomp the beast every now and then. I've got Flowmasters on mine too. I think they gave me at least a half mile to the gallon better gas. But i did strap them on only a few months after i had the truck so I really don't know. But right now it says 16mpg all around. I'll reset it tommorow but im pretty sure somewhere in the 16's is the best you can get with just the exhaust done.