This is what I get too, I generally run the Spartan 275 and up tunes. I don't think you are doing anything wrong.I have H&S, a 4" MBRP with DPF delete, and stock intake. BEST ive seen using both the 250 or hot damn 300 tune is 13.7 in town, and 17 on the freeway with the cruise set. Most of the time its around 16.3 on the freeway.... What am i doing wrong??? I cant believe you guys claim this kind of MPG! Is it the H&S thats killing me? Im half tempted to sell it and try the IDP tunes! I thought from everything I read that this 6.4 would kill my 6.0 in MPG, not the case.
I love the performance of the H&S but id be more then willing to give up some power for some MPG! Any help here?