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Keeping Your Vehicle in Shape

Keep Your Engine Properly Tuned
Getting a tune-up

Fixing a car that is noticeably out of tune or has failed an emissions test can improve its gas mileage by an average of 4%, though results vary based on the kind of repair and how well it is done.

Fixing a serious maintenance problem, such as a faulty oxygen sensor, can improve your mileage by as much as 40%.1

Fuel Economy Benefit: 4%
Equivalent Gasoline Savings:
$0.12/gallon
Keep Tires Properly Inflated
Sample tire pressure label

You can improve your gas mileage by up to 3.3% by keeping your tires inflated to the proper pressure. Under-inflated tires can lower gas mileage by 0.3% for every 1 psi drop in pressure of all four tires. Properly inflated tires are safer and last longer.1

The proper tire pressure for your vehicle is usually found on a sticker in the driver's side door jamb or the glove box and in your owner's manual. Do not use the maximum pressure printed on the tire's sidewall.

Fuel Economy Benefit: Up to 3%
Equivalent Gasoline Savings:
Up to $0.09/gallon
Use the Recommended Grade of Motor Oil
API energy conservation label

You can improve your gas mileage by 1%–2% by using the manufacturer's recommended grade of motor oil. For example, using 10W-30 motor oil in an engine designed to use 5W-30 can lower your gas mileage by 1%–2%. Using 5W-30 in an engine designed for 5W-20 can lower your gas mileage by 1%–1.5%. Also, look for motor oil that says "Energy Conserving" on the API performance symbol to be sure it contains friction-reducing additives.1

Fuel Economy Benefit: 1%–2%
Equivalent Gasoline Savings:
$0.03–$0.06/gallon
Replacing a Clogged Air Filter on Modern Cars Improves Performance but Not MPG
Air Filter

Replacing a clogged air filter on vehicles with fuel-injected, computer-controlled gasoline engines—such as those manufactured from the early 1980s to the present—or diesel engines does not improve fuel economy, but it can improve acceleration.

Replacing a clogged air filter on an older vehicle with a carbureted engine can improve both fuel economy and acceleration by a few percent under normal replacement conditions.2, 3, 4

Note: Cost savings are based on an assumed fuel price of $3.06/gallon.
View Data Sources...
  1. Estimates for fuel savings from vehicle maintenance, keeping tires properly inflated, and using the recommended grade of motor oil based on Energy and Environmental Analysis, Inc., Owner Related Fuel Economy ImprovementsAdobe Acrobat Icon, Arlington, Virginia, 2001.
  2. Thomas, J., West, B., Huff, S. 2013. Effect of Air Filter Condition on Diesel Vehicle Fuel EconomyAdobe Acrobat Icon. SAE Technical Paper 2013-01-0311.
  3. Thomas, J., West, B., Huff, S., and Norman, K. 2012. Effect of Intake Air Filter Condition on Light-Duty Gasoline Vehicles. SAE Technical Paper 2012-01-1717.
  4. Norman, K., Huff, S., and West, B. 2009. Effect of Intake Air Filter Condition on Vehicle Fuel EconomyAdobe Acrobat Icon. ORNL/TM-2009/021. Oak Ridge National Laboratory.