A Properly Tuned Engine

Fixing a car that is out of tune or has failed an emissions test can improve its fuel economy by an average of 4 percent. Results may vary based on the repair and how well it is done. Fixing serious maintenance problems, for example a faulty oxygen sensor, can improve your fuel economy by as much as 40 percent.

Fuel Economy Benefit: 4%

Properly Inflated Tires

Improve your fuel economy by around 3 percent by inflating tires to the proper pressure. Properly inflated tires are safer and last longer, while under-inflated tires can lower fuel economy.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%

Use Motor Oil that is the Recommended Grade

Using the manufacturer’s recommended grade of motor oil can improve your fuel economy by 1-2 percent. For instance, using 10W-30 motor oil in an engine designed to use 5W-30 can reduce your fuel economy by 1-2 percent.

Fuel Economy Benefit: 1-2%

Changing Spark Plugs

Ensure the engine’s spark plugs are changed at the manufacturer’s recommended specifications. These specifications can be supplied by the dealership or found on a chart in the owner’s manual. One single misfiring spark plug can reduce fuel economy by 10%. Therefore, for every 1000 kilometres you drive, you are paying for an extra 100 kilometres.

Fuel Economy Benefit: up to 10%

Replacing Clogged Air Filter in Older Cars (pre 1980s)

Tests suggest that replacing a clogged air filter on an older car with a carbureted engine may improve fuel economy 2 to 6 percent under normal replacement conditions. Replacing the filter could improve fuel economy up to 14 percent if the clogged filter is significant. Replacing a Clogged Air Filter on Modern Cars Improves Performance but not fuel economy.

Fuel Economy Benefit: up to 14%

Check Wheel Alignment

An alignment of your four wheels will enable the vehicle to drive straight down the road with the tires pointed straight ahead. The reduction in rolling resistance will improve fuel economy.

Clear Trunk

Remove unnecessary weight from your vehicle as more weight requires more fuel to accelerate. The lighter your car, the less fuel is required.
Data Sources

Information on the impact of air filter condition on fuel economy is based on a study by Kevin Norman, Shean Huff,
and Brian West, Effect of Intake Air Filter Condition on Vehicle Fuel Economy, Oak Ridge National Laboratory, 2009.

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 Improvements, Arlington, Virginia, 2001.