3. Change your oil
Using an energy conserving or synthetic motor oil can also improve gas mileage, saving you money at the pump. By reducing engine friction, these oils can improve engine efficiency by 1 to 2 percent, which in turn improves gas mileage. Be sure to use the recommended oil viscosity range for summer, which may be a bit thicker than winter. Always refer to your vehicle owner’s manual for the recommended oil type and viscosity. Most vehicle manufacturers recommend 5W-30 oil for year-round protection.