Ford Motor Co. has made improvements to the 2007 Ford Focus, with powertrain engineers concentrating on the 2.0-liter inline four-cylinder and improving fuel mileage.Nicholas Schubeck, supervisor, Powertrain Calibration for Ford Motor Company, explains that the Focus engine was originally calibrated for emissions. He says engineers noticed during testing that better fuel mileage could be achieved by making some adjustments to the calibration while still meeting emissions requirements.The team increased the engine’s spark and revised the exhaust-gas recirculation and intake manifold runner control (IMRC) schedules. The IMRC is a device on the intake manifold that increases the velocity of the air going into the cylinder at low speeds. Increasing air velocity helps maintain proper air-fuel ratios.This change, along with tire improvements, accounted for a 3-mile-per-gallon improvement on the EPA highway fuel economy label for five-speed manual models. The 2007 base Focus models come equipped with 14-inch Hankook tires that offer better rolling resistance than the 2006 model.Schubeck says customers will also notice an enhancement in performance. The extra engine spark improves acceleration, and the refinements to the engine have eliminated the hesitation that normally occurs when the air conditioning is in operation.