It's a toss-up nowadays as to whether an automatic or manual will get the ultimate economy, but the best numbers among the conventional Fusion powertrains are the 25 city / 37 highway miles per gallon returned by the six-speed-manual-equipped FWD Fusion with the 179-horsepower 1.6-liter EcoBoost motor. Numbers for the six-speed automatic are right behind, at 23 city / 36 highway.
Dropping nine horsepower and a turbocharger will get you price but not efficiency gains, with the 170-hp naturally-aspirated 2.5-liter four doing 22 city / 34 hwy. In the other direction, that's one small mpg away from the 22 hwy / 33 city to be had by the 237-hp 2.0-liter turbo four-cylinder. Add all-wheel drive to the equation and pay a 2-mpg penalty, with the 237-hp motor doing 22 city / 31 hwy when turning all four wheels.
Of course the hybrid Fusion killed it, getting 47 city and 47 hwy. That is only bested by the 2012 Toyota Prius C and Prius, ties the 2013 Ford C-Max Hybrid and beats the 2012 Honda Civic Hybrid. Among its competitors, the Fusion is in the mosh pit with the 2012 Toyota Camry's 25 city / 35 hwy, the Honda Accord's 27 city / 37 hwy and the Chevrolet Malibu's 22 city / 34 hwy, with just the sedan-surfing Nissan Altima jumping out at 27 city / 38 hwy.