I just dont see how it is possible to get that bad of gas mileage on a crossfire. It would have to run like total crap, I think your conversion math is off. Even my modded srt6 would avg 19mpg.

Now my Ram SRT-10, that thing got 9 mpg mo matter what you did but that was a 5200 pound 6 speed truck with a 8.3 liter viper v10. You could see the gas gauge moving down if it idle for a long time, haha.