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The Top Seven Fuel Mileage Misconceptions

There is a lot of free advice floating around these days on how to maximize a vehicle’s fuel mileage. The amount you hear seems to increase proportionally with the price of gas. But is that coffee shop wisdom always good advice?

According to a press release from the North Dakota State University (NDSU), the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Energy recently teamed up to take a look at a few of those popular beliefs. You may find some of their conclusions a little surprising.

Here’s a look at the top seven busted myths.

STICK SHIFTS USE LESS

Think that manual transmissions use less fuel? Thanks to computer-controlled shifting, modern vehicles with automatic transmissions can get about the same or even better mileage than similar models with a standard transmission.

COLD ENGINES USE MORE FUEL

Do vehicles need to warm up before being driven? Actually, a vehicle that is idling is getting zero miles per gallon, so minimizing idling can improve fuel economy. While allowing vehicles to warm up in northern climates may make the ride more comfortable, you can drive almost immediately after startup without being concerned about engine or drivetrain damage. You should, however, allow the engine to reach a normal operating temperature before asking it to do any heavy lifting.

FUEL ECONOMY ERODES OVER TIME

Does fuel economy drop as a car ages? Fuel economy varies with the number of miles you drive per year, however, according to the EPA, a vehicle’s mileage will improve for the first few years and will not decline much as long as the vehicle is maintained properly.

DIRTY FILTERS EAT MILEAGE

Contrary to popular belief, dirty air filters do not reduce fuel economy. Recent studies have shown that fuel-injected engines can compensate for dirty air filters without reducing fuel economy. Dirty air filters may impact a vehicle’s performance but should not affect the mileage until the air filter is so clogged that the vehicle has noticeable performance issues.

ADDITIVES BUMP EFFICIENCY

Think gas additives and devices save on fuel? Of all the additives and devices the EPA has tested, none has improved fuel economy significantly and some may even harm a vehicle. The EPA has tested more than 100 alleged fuel-savings devices, not one improved mileage more than a minor amount.

RE-STARTS SUCK FUEL

Starting a vehicle uses more fuel than leaving it idling, right? Wrong. The fuel-injection systems used in vehicles today will start a vehicle very efficiently. If you need to idle for more than a minute or two, you should shut the engine off. In fact, Natural Resources Canada’s (NRC) Office of Energy Efficiency also has something to say on this topic. According to them, the extra amount of fuel required on start up for the average vehicle is only equal to that used for ten seconds of idling. Their website goes on to say that only 10 minutes of unnecessary idling per day can add five per cent to an annual fuel bill. If your reason for allowing a vehicle to idle excessively is concern about adding extra wear and tear to the starter, the NRC says get over it. The added use has virtually no effect on a starter’s life.

PREMIUM FUEL IMPROVES MILEAGE

Is premium fuel is more efficient? Unless your owner’s manual specifically calls for premium fuel or your vehicle will not run smoothly on regular gas, using premium isn’t likely to significantly increase fuel economy.

For more reading on fuel economy, check out the NRC’s website at http://oee.nrcan.gc.ca, or the EPA’s at www.fueleconomy.gov.

ScottGarveyismachineryeditorforGrainews.

Contacthimat [email protected]

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Scott Garvey

Scott Garvey is a freelance writer and video producer. He is also the former machinery editor at Grainews.

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