AutoMD.com, a free auto-repair Web site, has released its Top Fives for Fuel-Efficient Summer Drives — five mechanical tips and five driving habits.
Replace/tighten your gas cap: Fuel evaporates through gas caps with broken or weak seals, potentially reducing your efficiency by 2 percent, polluting the air and allowing contaminants and dirt into your fuel.
Inflate your tires: Underinflated tires have a higher rolling resistance, which reduces efficiency. By keeping your tires inflated to the proper pressure, you can improve your gas mileage by up to 3.3 percent.
Change your oil: By using energy-conserving or synthetic motor oil, you can reduce engine friction, improving efficiency by 1 to 2 percent.
Replace spark plugs: Misfiring spark plugs can reduce fuel efficiency by as much as 30 percent, or 75 cents a gallon.
Replace the air filter: Replacing a clogged air filter on a car with a carburetor may improve fuel economy up to 14 percent, depending on how dirty the filter is.
Cruise, don't speed: Each 5 mph you drive over 60 is like paying an extra 24 cents a gallon for gas. Use cruise control to smooth your throttling and keep your speed steady. This, however, doesn't work on hilly terrain.
Get the lead out: Rapid acceleration and braking can increase fuel burn by as much as 40 percent and makes toxic emissions five times higher. Gradually increase speed and start slowing sooner into a stop to improve your mileage.
Avoid idling: Turn off your engine if you are stopped for more than 30 seconds. When you idle, you are getting no mpg, adding to pollution and wasting money. Two minutes of idling uses one mile worth of gasoline.
Get the lead out II: Your car is not a storage unit. An extra 100 pounds can reduce fuel economy 1 to 2 percent.
Turn off the A/C. Turn on the ventilation. Roll up the windows: Air conditioning or open windows make your vehicle less fuel-efficient. But on the hottest days, turn off you're A/C and roll down your windows when driving around the neighborhood or in city traffic, and do the opposite on the highway — driving fast with the windows open can burn more fuel than A/C.