http://www.ehow.com/guide_7-http://www.ehow.com/guide_7-cars.html.htmlwww.ehow.comhttp://www.ehow.com/how_5113320_purpose-car-air-filter_.htmlThe purpose of a car's air filter is to filter the air that is coming into the carburetor or fuel intake system, and a dirty air filter may restrict airflow into the intake manifold. Find out how a dirty air filter may cause an engine to burn excessive fuel with help from an ASE-certified technician in this free video on car air filters. Published on 6/23/2009