Gas Type by Car: Regular, Premium, Diesel or E85 / Buick / Park AvenueBuick Park Avenue Gas type by year YearGas type2005Depends on engine: premium or regular2004Depends on engine: regular or premium2003Depends on engine: premium or regular2002Depends on engine: premium or regular2001Depends on engine: regular or premium2000Depends on engine: regular or premium Source: U.S. EPA / DOE fuel economy data (fueleconomy.gov).