It takes more fuel to start a vehicle than it does to let it idle.
People are really confused about this one, and will leave a car idling for half an hour rather than turn it off and restart. Some kids I know started an anti-idling campaign in the suburbs and are shaming parents into shutting down their cars. Idling uses a quarter to a half gallon of fuel in an hour (costing you one to two cents a minute). Unless you're stalled in traffic, turn off the car when stopped for more than a few minutes.
Vehicles need to be warmed up before they're driven.
Pshaw. That is a long-outdated notion. Today's cars are fine being driven off seconds after they're started.
As a vehicle ages, its fuel economy decreases significantly.
Not true. As long as it's maintained, a 10- or 15-year-old car should have like-new mileage. The key thing is maintenance: An out-of-tune car will definitely start to decline mileage-wise.
Replacing your air filter helps your car run efficiently.
Another outdated claim, dating back to the pre-1976 carburetor days. Fuel-injection engines don't get economy benefits from a clean air filter.
Aftermarket additives and devices can dramatically improve your fuel economy.
As readers of my story on The Blade recall, there's not much evidence that these "miracle products" do much more than drain your wallet. Both the Federal Trade Commission and Consumer Reports have weighed in on this. There are no top-secret 100-mpg bolt-ons out there.
Using premium fuel improves fuel economy.
You might as well write a check to BP if you believe this. Only use premium if your car specifies it.