Some of what you know about fuel economy may be wrong, and it could cost you money every time you get behind the wheel. • To set the record straight in time for summer driving season, the Environmental Protection Agency presents "the top 10 misconceptions about fuel economy." • Here are some of the myths:
Using premium gasoline will improve your fuel economy: If you had a dime for every dollar people have squandered pumping premium into cars that don't need it, you'd never worry about gasoline prices again. Using a higher fuel grade than the automaker recommends will almost certainly have no effect on your fuel economy. However, pumping a lower grade than recommended can damage your engine and will probably increase fuel consumption and cost you money.
Smaller vehicles always get better fuel economy: Hybrids, diesels, new technologies and smart engineering can create vehicles that combine fuel efficiency with room and comfort.
A manual transmission will give you better fuel economy than an automatic: Modern automatic transmissions often provide better fuel economy than a manual, thanks largely to extra gears and electronic controls.
Vehicles need to warm up before you drive them: Electronic engine controls mean a modern vehicle is running at or near maximum efficiency as soon as you start it. Letting the car warm up for a few minutes simply wastes fuel.
Aftermarket additives will dramatically improve your fuel economy: Forget it. They're more likely to damage your engine or increase your tailpipe emissions. For more information on this, go the Federal Trade Commission's website (www.ftc.gov) and enter Gas-Saving Products: Fact or Fuelishness? in the search box.
It takes more fuel to restart the engine than let it idle: This was true when inefficient carburetors metered fuel use, but modern fuel injection means that you save energy by turning the engine off. This does not mean you should shut the engine off at every stoplight or when you're waiting in line. That can wear out your starter and slow all the other drivers, irritating them and leading to wasted fuel in all the vehicles. However, stop-start systems that efficiently shut the engine off are a key part of how hybrids save fuel. Nearly every new vehicle will have a fast and efficient automatic stop-start feature in a few years.
The window-sticker mileage figures are a guarantee of the mileage you'll get: Not even close. How you drive has a massive impact on your mileage. However, the window-sticker figures are the only way to realistically compare fuel economy and operating costs when you shop for a new vehicle. The numbers are generated in lab tests, so every vehicle is held to the same standard. "Your mileage will vary" as the fine print says, but you can trust that a higher EPA rating will save you money.
Fuel economy ratings
Manual or automatic? A 2011 Mustang V-6 gets better fuel economy with an automatic transmission than with a manual.
Bigger or smaller? A manual-transmission Honda Fit subcompact has the same 29 mpg combined city/highway EPA fuel economy rating as a larger Honda Civic with a manual transmission.
Rated or unrated? The EPA will not rate the fuel economy of Nissan's new commercial van because the NV is so heavy it falls outside the EPA's authority.
Source: Mark Phelan
10 misconceptions about fuel economy
• You have to drive a small car to get good fuel economy.
• Manual transmissions always get better fuel economy than automatics.
• It takes more fuel to start a vehicle than it does to let it idle.
• Vehicles need to warm up before they can be driven.
• As a vehicle ages, fuel economy decreases significantly.
• Replacing your air filter will help your car run more efficiently.
• Aftermarket additives and devices can dramatically improve your fuel economy.
• Using premium fuel improves fuel economy.
• The EPA fuel economy estimates are a government guarantee on what fuel economy each vehicle will deliver.
• All vehicles are tested for fuel economy.
Source: Environmental Protection Agency