From Treehugger.com - some great tips for saving money while traveling.

66 Ways To Save Money on Gasoline

by Mark Ontkush, Boston, Massachusetts, USA on 06.23.08

While the rising cost of oil has the price of gasoline skyrocketing faster than global warming is melting glaciers, people everywhere are preparing for cross-country road trips to Grand Canyon National Park and summer camps in Maine. We can't really argue with that innate desire to get closer to nature and out on the open road, and whether you're a die-hard cyclist or a still driving an SUV, chances are you plan to get in a car to go somewhere this summer. So whether you're packing up the Prius for some close-to-home camping, towing the boat to far-away shores, or merely fighting the crosstown traffic, these money- and gas-saving tips are designed to help you squeeze every last bit of power out of that precious petrol--and cause fewer CO2 emissions, too. It's a comprehensive list--several tasks should be done before even starting your car; others require minor adjustments to your driving style. All of them aim to help you drive a little greener.

Gas-Saving Tips: Questions to Ask Before You Turn on the Engine

1. Is your engine tuned up? Fixing a car that is out of tune (or has failed an emissions test) will boost gas mileage, so be sure to give your car regular tune-ups. You'll also want to watch out for worn spark plugs. A misfiring spark plug can dramatically reduce a car's fuel efficiency.

2. Is your body in good shape?
Inspect suspension and chassis parts for occasional misalignment. Bent wheels, axles, bad shocks, broken springs, et cetera create engine drag and are unsafe at high traveling speeds.

3. Is your air filter clean?
When the engine air filter clogs with dirt, dust and bugs, it causes your engine to work harder and your car becomes less fuel-efficient. Replacing a clogged air filter could improve your gas mileage by as much as 10 percent. It's a good idea to have your engine air filter checked at each oil change.

4. What grade is your oil?
You can improve your car's gas mileage by using the manufacturer's recommended grade of motor oil. Opt for motor oil with the words "energy conserving" on the API performance label; this oil contains friction-reducing additives.

5. Got shade?
Buy a good windshield shade. A windshield shade blocks sunlight and helps to keep heat out of the inside of your car. This will help reduce air conditioning use in the summer.

Ways to Save Money on Gas at the Pump

6. Don't overfill 'er up. Avoid filling your gas tank to the top. Overfilling results in sloshing over and out of tank. Never fill gas tank past the first "click" of fuel nozzle if the nozzle is automatic.

7. Use the lowest octane you can.
Buy the lowest grade or octane of gasoline that is appropriate for your car; pricey premium fuel won't boost your car's fuel economy. [some readers say premium is premium, see comments mjo]

8. Tighten that cap.
Gas will evaporate from your car's gas tank if it has an escape. Loose, missing, or damaged gas caps cause millions of gallons of gas to evaporate each year.

9. Wait until you're near empty.
Don't fill up until your tank is near empty; this will extend your gas because you are hauling a lighter load as the tank nears empty.

10. Find credit card discounts.
Some credit cards offer gas savings when you use the card for purchases. This works in much the same way that some credit card companies give you frequent-flier miles when you use their card for purchases.

11. Membership has its privileges.
Some gas stations offer membership benefits. There are also department and grocery stores that give discounts at the fuel pump when you use their store membership cards.

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