With the option of a four-cylinder in the lineup, fuel economy for the 2014 Mercedes-Benz C-Class can be quite good. However, if you're looking for the monstrous C63 AMG, it can be pretty bad, too.
It's no surprise that the powerful C63 AMG, with its huge V-8, is something of a boat anchor for fuel economy--even though it's a rocket ship in performance. It scores an estimated 13/19 mpg for 15 mpg combined according to the EPA.
The C250 sedan scores 21 mpg city and 31 mpg highway for 25 mpg combined, according to the EPA. The C250 coupe matches the sedan's figures.
The C300 4MATIC and C350 sedan are rated the same, at 20 mpg city and 29 mpg highway for 23 mpg combined. At 19/28 mpg, the C350 coupe scores slightly worse.