Gas Type by Car: Regular, Premium, Diesel or E85 / Mazda / CX-7Mazda CX-7 Gas type by year YearGas type2012Depends on engine: premium or regular2011Depends on engine: premium or regular2010Depends on engine: premium or regular2009Premium2008Premium2007Premium Source: U.S. EPA / DOE fuel economy data (fueleconomy.gov).