As gas prices skyrocket, let’s examine some commonly held beliefs about how to get the best gas mileage from your vehicle.

FACT: Driving slower saves you gas. Like millions of Americans, we listen to the “Car Talk” guys on National Public Radio mostly because they make us laugh. But they also dispense great auto advice, and they stress that slowing down makes a big difference:

For every 1,000 miles you drive (figuring gas at $2.50 a gallon and 25 mpg fuel efficiency), you’ll save as much as $15 driving 10 mph slower. Of course, if gas is nearly double that price, the savings should double as well. Something to think about if you’re a speed demon.

FICTION: Replacing the air filter on your car improves mileage. The U.S. Department of Energy reports that an air filter change will mostly help your acceleration, not your mileage — though if you drive an older car with a carbureted engine, it may improve fuel economy 2% to 6%.

FACT: Stepping on the brakes wastes gas. Every time you use the brakes, you’re wasting the ‘acceleration’ you’ve already used. Instead of moving your car, that energy is being transformed into steaming hot brake pads. Instead, learn to anticipate stops, and gently accelerate your car from a standing stop.

FICTION: Gas-saving additives can improve fuel economy by 20% or more. What’s the difference between motor oil and snake oil? Not much, if you’re weighing the claims of slick entrepreneurs who know the timing’s right for selling you magical gas-saving potions. To be sure, some long-standing products with modest claims (such as STP Gas Treatment) have vigorous supporters, but they only claim to boost mileage about 10%.

But as the Federal Trade Commission warns, “The Environmental Protection Agency has evaluated or tested more than 100 alleged gas-saving devices and has not found any product that significantly improves gas mileage. In fact, some ‘gas-saving’ products may damage a car’s engine or cause substantial increases in exhaust emissions.”

FICTION: New “low-resistance” tires significantly improve gas mileage. Unless you’re driving bald or severely underinflated tires, the hype about low-rolling resistance tires adds up to minimal gas savings. As this story by USA Today reports, various brands of these newfangled tires create gas savings of only 1% to 3%, even if rolling resistance is cut by 25% or more. Whether that saves wear and tear on your car is another story, but the mileage improvements won’t even pay for a spare tire over the course of 10 tanks of gas.

You can realize dramatic mileage improvement by replacing your oxygen sensor. This falls under the category of tuning up your car, always a good idea if you want to see gas mileage gains in the 4% range. As a function of any proper tuneup, ask your Rolf’s mechanic to look at the oxygen sensor; if it’s not working properly, a simple repair to this part could boost your mileage by as much as 40%, the U.S. Department of Energy states.

Note that if you make this fix, it may take a few weeks for you to realize the improved mileage as your engine’s fuel-air ratio adjusts.

FICTION: Topping off the gas tank is a good idea. We know, We know: You’ve finally found the one pump between here and Logansport, Ind., that has affordable gas, so why not squeeze every last drop into your tank? While that sounds sensible at first blush, here’s the problem: Gas expands in warmer weather, which means topped off gas will likely wind up spilling out your tank.

As if you needed more incentive, check out this warning from the U.S. Environmental Protection Agency: “Topping off the gas tank can result in your paying for gasoline that is fed back into the station’s tanks because your gas tank is full.” So unless you’re in the mood to pay the folks at Exxon or BP a little more for your fuel, stop topping off your tank.

FICTION: High-octane gasoline improves your mileage. We’re amazed to see that countless drivers still fall for this marketing gimmick, despite abundant evidence that high-octane gas is a waste of money. Props to the folks at for pointing this out, along with other gas-saving tips you can read here. Bottom line: Unless your car specifically requires premium, skip it and go for low-octane fuel.

*From MSN Money, April 2012[/fusion_builder_column][/fusion_builder_row][/fusion_builder_container]

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