Ford Fiesta engine is a 1.6-liter Duratorq TDCi (diesel) that has been tweaked for efficiency. Fuel economy for the ECOnetic Fiesta is 3.7 L/100km (63.6 mpg US) combined, or 3.2 L/100km (73.5 mpg US) on the highway. The Fiesta Econetic uses a bunch of tricks to reduce fuel consumption, things like improved aerodynamics (its coefficient of drag is 0.33), weight reduction, low rolling resistance tires, and enhanced lubrication. The Ford Econetic Fiesta would undoubtedly be a big hit in the USA (especially with the biodiesel crowd), but unfortunately, Ford will only sell them in Europe for now.