Gas saving myths

Think you're stretching out your gas dollars by not running your car's air conditioning? Think again.

NEW YORK (CNNMoney.com) -- Gas prices are on the rise again. This time it's the crisis in the Middle East that has motorists paying more at the pump. In today's top 5 Tips we're going to help you make the most of your fuel economy by debunking some gas-saving myths.

MYTH 1 - It's all about your MPG rating

How you drive can be more important than your car's miles per gallon rating given by the Environmental Protection Agency. In fact, those MPG ratings are way outdated. In fact, EPA ratings were off about 14 percent on average, according to Phillip Reed of Edmunds.com.

"The standards were implemented in the 70s. People drive more aggressively today. We spend more time stuck in traffic. We cruise at higher speeds," he says.

On the plus side, the EPA will upgrade these standards in 2008. To get real-world fuel economy estimates check out consumerreports.org and Edmunds.com.

MYTH 2 - Gas saving products help fuel efficiency

You may have seen some products that claim to increase your gas mileage up to 20 percent. These products can be oil or gasoline additives that cost anywhere from $5 to $100. Don't fall for the hype.

The Environmental Protection Agency concluded that no product significantly improves gas mileage. And in fact, these products may even damage your engine. If you've already purchased one of these products, get a refund even if the money-back guarantee has expired, says the Federal Trade Commission.

MYTH 3 - You need the best octane

Most engines are designed to take regular unleaded gasoline, which has an octane rating of 87. Using higher octane premium gas in an engine that is designed to run on regular doesn't improve performance.

And even engines where it's recommended you use premium gas can run on regular without any problems. The bottom line here is that paying for premium gas is usually a waste of money.

MYTH 4 - All gas rebate cards are created equal

Gas rebate cards can give you anywhere from 3 to 5 percent rebate on your fill-up. And that can add up to some real value at the end of the year. But there are some major differences between cards. Look specifically at card fees.

Some cards have annual fees of $20, according to Curtis Arnold of cardratings.com. Interest rates on these cards can also vary from 13 percent to over 20 percent. And be vigilant when it comes to expiration dates as the rebate can expire in as little as six months. It pays to do your homework here. Consumers can compare the benefits of these cards at cardratings.com or cardweb.com.

MYTH 5 - Air conditioning wastes gas

Temperatures are in the triple digits in some places nationwide and if you have air conditioning, of course you're going to use it.

But you don't have to feel guilty about cranking up your car's AC. According to Edmunds.com, the air conditioning compressor does pull power from the engine wasting some gas, but the effect is minimal in modern cars. On the other hand, driving with your windows down at high speeds can create an aerodynamic drag.

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