KEEP TIRES PROPERLY INFLATED
You can improve your gas mileage by around 3.3 percent by keeping your tires inflated to the proper pressure. Under-inflated tires can lower gas mileage by .04 percent for every 1 psi drop in pressure of all four tires. Properly inflated tires are safer and last longer. You can locate proper tire pressures on your driver's side door sticker and also in your owner's manual.
Fuel Economy Benefit: up to 3%
Equivalent Gasoline Savings: up to $0.12/gallon
USE THE RECOMMENDED GRADE OF MOTOR OIL
You can improve your gas mileage by 1-2 percent 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 ½ percent. Using 5w-30 in an engine designed for 5w-20 can lower your gas mileage by 1-1.5 percent. Also, look for motor oil that says "Energy Conserving" on the API performance symbol to be sure it contains friction-reducing additives.
Fuel Economy Benefit: -2%
Equivalent Gasoline Savings: $0.04-0.08/gallon
Note: Cost savings are based on an assumed fuel price of $4.08