Not sure about gas milage my needle bounces as well, and i am just now getting it around to putting it on the road, yeah no ac i run with the windows down. I have the compressor etc, but yanked it all out. I am figuring around 10-12mpg depending on my foot. It has a 3.73 running gears but a 700r4 built tranny so that should help some. I love the fact that it has saddle bags so that is nice except for the filling part and speaking of which i have to run 97 or better since my compression ratio is 10.5/1.