Your car burns gas for energy. It’s food for the engine, which is what makes the car run. The more work the car has to do, the more energy it needs. It’s sort of like how a marathonerneeds to eat a lot more than a couch potato (though couch potatoes may beg to differ). This principle is already pretty clear to most people. It’s why large SUVs have worse gas mileage than small cars. The added weight of the SUV makes the car work harder.
No matter what kind of car you drive, eliminating weight can go a long way toward increasing your car’s fuel efficiency. Now, before you take a chainsaw to the bumper, there are probably less drastic steps you can take. Have a ski or bike rack on your car? Unless you’re on your way to a ski trip or bike ride, take it off. That unused rack adds weight and wind resistance. And if you’re like most people, you probably have some junk in your trunk. Clean it out. Sports equipment, strollers, gym bags and rock salt left over from winter driving are all hurting your fuel economy. The EPA estimates that for every extra 100 pounds your car caries, it loses 2 percent in fuel economy, so just by cleaning up your act, you can start on the road to saving [source: fueleconomy.gov].