Here are some tips for improving your gas mileage.

1. Change your spark plugs
2. Drive slower. The faster you drive, the more fuel you use. For example, driving at 65 miles per hour (mph), rather than 55 mph, increases fuel consumption by 20 percent. Driving at 75 mph, rather than 65 mph, increases fuel consumption by another 25 percent.
3. Use overdrive gears. Overdrive gears improve the fuel economy of your car during highway driving.
4. Use cruise control. Using cruise control on highway trips can help you maintain a constant speed and, in most cases, reduce your fuel consumption.
5. Avoid unnecessary idling. Turn off the engine if you anticipate a lengthy wait. No matter how efficient your car is, unnecessary idling wastes fuel, costs you money and pollutes the air.
6. Remove excess weight from the trunk. An extra 100 pounds in the trunk reduces a typical car's fuel economy by one to two percent.
7. Keep your engine tuned. Studies have shown that a poorly tuned engine can increase fuel consumption by as much as 10 to 20 percent depending on a car's condition.
8. Keep your tires properly inflated and aligned. Under-inflated tires cause fuel consumption to increase by six percent.
9. Check and replace air filters regularly. Not only will replacing a dirty air filter improve your fuel economy, it also will protect your engine. Clogged filters can cause up to a 10 percent increase in fuel consumption.

Source: FAQFarm.com