i found differnt brands of gas make a differance with me, i drive from indy to detroit every weekend putting about about 800 miles on it in the round trip plus weekly driving, if i fill up with marathon or shell i get 25.6-26.2 mpg with cruse set at 75mph, if i fill up with BP, i loose about 1.5 mpg and if i go with the no names i loose up to 3-4mpg