Some user has entered incorrect data leading to an mpg average of >500mpg. This throws off the overall mpg calculation for that car make. See http://www.fuelly.com/car/honda/cr-z/2011 and search for "556". Any provision for excluding/fixing this user's car data?
Sure, you can go to the car profile page and use the Report This Page feature at the bottom of the page. We check those flags every couple days and filter those vehicles out of public browsing if it seems like they've entered bad data.