Ok, this is my 3rd fusion, had a 2007, a 2010 and now a 2013 SE. I do 100% city driving and my city is "Speed Hump" crazy. This has a lot to do with mpg. In addition, the fusion auto transmission is capable of learning your driving habits. If you have bad habits while driving, your transmission begins to drive badly as well. So, every 2,000 miles or so, I disconnect the battery for about 10 minutes, this resets the transmission.
My car was getting about 18 mpg, I did a reset and it now is averaging 21.6 (city) which is "in-line" with Fords city estimate of 22 mpg. Just a tip to help you gas conscience drivers.