I haven't actually tested any myself, but many japanese automakers overstate their mpg ratings (per magazine articles i've read). It's unfortunate, but true. A honda, like the fit, with 109 hp, 4cyl engine, and being fairly lightweight, should be getting around 30mpg in the city and upwards of 35mpg on the highway, maybe more under good driving conditions with decent gas. I would fill up at a different fueling station and see what happens. Are you using E85 fuel or any other ethanol based fuel? You'll get much less MPG with that. If getting decent gas doesn't fix the problem. Take it back to Honda and get another one (or at least have them evaluate your current vehicle) If they can build a civic that gets more than 35 mpg, then they can build a fit that gets even more. Good luck -