The carburetor mixes air with fuel so that it burns more easily in the engine. A vacuum caused when your car's pistons make their downward stroke pulls air into the carburetor.

Even the cleanest gasoline may contain small amounts of water and dirt. Your car's fuel filter helps protect fuel system components by removing these contaminants before they get to the engine.

Fuel injection is the method of mixing fuel and air that's used in virtually all newer model engines. Fuel injectors use electronic controls to spray precise amounts of fuel into the intake air.

Because they're especially sensitive to water in the fuel, diesel engines have a special kind of filter called a water separator. Even a tiny amount of water can wreak havoc on a diesel engine.