Gas Pains: Mileage Myths and Misconceptions

Found this to be really good read at Car & Driver....
Yes, get rid of the junk in your trunk. And the rack on your active-lifestyle roof.

BY MICHAEL AUSTIN, PHOTOGRAPHY BY TOM COSGROVE, ILLUSTRATION BY TOM COSGROVE December 2008

Read more Gas Pains coverage: Destination: 35 MPG

Quickie quiz: True or false?
A. Lukewarm water freezes more quickly than cold water.
B. Penguins inhabit the North Pole.
C. Noodles were invented in Italy.
Fooled you on at least one, right? All of the statements are false even if they sound as though they could be true. There are a lot of popular conceptions—and misconceptions—about fuel economy as well. Some of them involve common sense, such as keeping your tires properly inflated, whereas others are myths that people accept as the truth. Because fuel efficiency is the new cause célèbre in the automotive world, we decided to test a few fuel-saving and/or fuel-sapping situations to see just how much of a difference these tactics can make.

Our test scenario was to drive around a 2.5-mile oval at steady speeds (35, 55, and 75 mph) and measure fuel economy from the vehicle’s OBD II data port. We repeated the circuits under a variety of conditions (cargo added, windows down, etc.) and compared the results. Each test involved just one vehicle, so the numbers you see here aren’t exactly cast in stone. But our findings do give us a good idea about the degree of effect that each situation has on fuel economy—the results may vary for different types of vehicles, but the general trends should be similar.

Here are all the things that they cover, just click on the title and it will take you to the article.

Turn Off Your Air Conditioner

When Coasting to a Stop, do Not Shift Into Neutral

Take the Junk Out of Your Trunk

Inflate Your Tires Properly but Beware of Overinflation

Take Everything Off the Roof

Turning Off the Car's Engine Saves Fuel When the Stops are Long, but It's Not a Good Idea For Short Stops

Keep the Convertible Top Up While Driving on Highways

Here's the link;
http://www.caranddriver.com/reviews/hot_lists/high_performance/features_classic_cars/gas_pains_mileage_myths_and_misconceptions_feature