Proper Tire Inflation
Photo of tire pressure being measured.
Properly inflated tires last longer, increase fuel economy, and are safer. Every decrease in pressure by 1 pound per square inch for four tires can decrease fuel economy by 0.2%. By keeping your tires properly inflated, you can improve your gas mileage by 0.6% on average, and up to 3%. Some fleets use nitrogen inflation, tire pressure monitoring systems (standard equipment in light-duty vehicles newer than model year 2007), and other technologies to maintain optimum tire pressure. To find the proper tire pressure for your vehicle, you can refer to the tire specifications provided by the manufacturer.
Recommended Motor Oil
Using the manufacturer's recommended grade of motor oil in an engine can improve fuel economy by 1%–2%. Check your owner's manual for the manufacturer's recommended grade of motor oil. Also, you may select motor oil that contains friction-reducing additives that improve fuel economy; look for oil labeled "Resource Conserving" on the American Petroleum Institute(PDF) service symbol. Drivers can also consider synthetic oils, which may improve fuel economy in light-duty vehicles by reducing friction in the engine.
Engine Tune-Ups
Regular engine tune-ups ensure that your vehicle is running efficiently and can save you time and money in the long run. Tuning a neglected vehicle or fixing one that failed an emissions test can increase fuel economy by an average of 4%, based on the repair type and quality. See your owner’s manual for manufacturer recommendations on when to get tune-ups. For more information on key maintenance areas to focus on to improve fuel economy, refer to the North American Council for Freight Efficiency's maintenance confidence report.
Reprinted fromafdc.energy.gov/.com article