Bad Oxygen Sensors and/or Air Filters. Bad oxygen sensors and air filters can reduce gas mileage by as much as 20%! It's a must to help keep oxygen sensors with a proper mix of air and fuel so they can perform optimally. Dirty air filters, clogged with sand and debris, simply need to be replaced so that the engine can perform at its peak. VAfromMN. 343 posts · Joined 2005. #8 · Nov 17, 2012. My '04 Focus SVT just turned 263,000 miles. All I've ever done is replace the wear items. Did my first timing belt at 150,000 and just did my second at 261,000 miles. All of the mechanicals are intact. I put new struts/shocks a couple of months ago. Used Ford Focus for Sale Near equal to 30% of the sale price up to a maximum credit of $4,000 for the purchase of a used plug-in electric or hydrogen fuel cell vehicle. 34 Combined MPG (30 The domestic 2013 Ford Focus is powered by a 2.0-liter inline four-cylinder gasoline engine that produces 160 horsepower (a 20 HP bump over the previous model). The Focus SFE is the most fuel-efficient model in the 2013 line up, achieving gas mileage ratings of 28 city and 40 highway miles per gallon, as it benefits from improved aerodynamics Annual Fuel Cost* $1,750: Cost to Drive 25 Miles: $2.89: Cost to Fill the Tank: $43: Tank Size: 12.4 gallons *Based on 45% highway, 55% city driving, 15,000 annual miles and current fuel prices. Fuel economy tests show that, in city driving, a conventional gasoline car's gas mileage is roughly 15% lower at 20°F than it would be at 77°F. It can drop as much as 24% for short (3- to 4-mile) trips. The effect on hybrids is typically greater. Their fuel economy can drop about 30% to 34% under these conditions. With the standard 2.0L engine, the Focus will achieve an EPA-estimated 25 city/34 highway MPG.*. This engine even gets slightly better mileage in the SE Hatch trim level with an EPA-estimated 26 city/38 highway MPG.*. When powered by the available 1.0L EcoBoost® engine, the fuel economy of the Focus jumps up to an EPA-estimated 30 city/40 Brezhbear fueled-up their 2010 Ford Focus. Last Tank: 32.0 MPG 7 hours ago; EuropoweR fueled-up their 2018 Ford Focus. Last Tank: 18.5 MPG 8 hours ago; Puckster02 added 1 notes for their 2015 Ford Focus. 10 hours ago-NooM-fueled-up their 2018 Ford Focus. Last Tank: 31.1 MPG 13 hours ago; myfordf350rocks fueled-up their 2004 Ford Focus. v2OHP.