Service porters are most commonly found in car dealerships. They maintain cars and trucks, take stock of vehicles on the lot, and document information on the cars. Other job duties include refilling tires and gas tanks, keeping batteries at full charge, and cleaning vehicles. As a service porter, you also accompany buyers on test drives and move cars into position for the best possible display. There are other kids of service porters, such as housekeeping porters used in the real estate and residential services industries.