Upgrade to premium and get better mileage? Nope? You're just throwing your money away, says the EPA.
Downsize to a small car, change your air filter every few months, let your cold car warm up before driving off, use premium fuel and aftermarket additives.
These are just some of ways not to improve your fuel economy. Conventional wisdom is often wrong, says the Environmental Protection Agency, which is tasked with tracking and regulating vehicle mileage under the Corporate Average Fuel Economy, or CAFE standards.
Even some of the most knowledgeable enthusiasts and experts may get it wrong when it comes to taking the right steps to improve mileage. In some cases, that’s because of changing technology, the EPA reports on fueleconomy.gov.
In the era of the carburetor, a dirty air filter had a direct and immediate impact on mileage, but “Modern computer-controlled, fuel-injected engines regulate the air-fuel mixture so well that a dirty air filter does not decrease fuel economy—although it can still affect performance,” the EPA notes.
You may also get a surprise when you check the mileage numbers for manual transmissions. Traditionally, sticks did better than automatics, but the latest automatics are lighter and more efficient, with lock-up torque converters that reduce losses, especially at highway speeds. The 2011 Ford Mustang V6 is a notable exampe, rated at 31 mpg Highway with the automatic gearbox, 29 mpg with the manual.
Even downsizing is no guarantee of better. Mustang’s numbers are actually better than a number of smaller cars, and with hybrid or diesel powertrains, some midsize models are outperforming subcompacts.
Here are the Top 10 Misconceptions About Fuel Economy, according to the EPA:
1. You have to drive a small car to get good fuel economy.
2. Manual transmissions always get better fuel economy than automatics.