1995 Pontiac Grand Am Owner's Manual - Page 213

Fuel Use regular unleaded gasoline rated at octane or 87 higher. It should meet specificationsASTM D4814 in the United States and CGSB 3.5-92 in Canada. These fuels should have the proper additives,so you should not have to add anythingto the fuel. In the UnitedStates and Canada, it's easy to be sure you get the right kind of gasoline (unleaded). You'll see UNLEADED right on thepump. And only unleaded nozzles will fit into your vehicle'sfiller neck. Be sure the posted octane is at least 87. If the octaneis less than 87, you may get a heavy knocking noise when you drive. If it's bad enough,it can damageyour engine. If you're using fuel rated at 87 octane or higher andyou still hear heavy hocking, your engine needs service. But don'tworry if you hear a little pinging noise when you're accelerating or driving up a hill. That's normal, and you don't have to buya higher octanefuel to get rid of pinging. It's the heavy, constant knock that means you have a problem. What about gasoline with blending materials that contain oxygen (oxygenates), such as MTBE or alcohol? I NOTICE: I If you try todo your own service work without knowing enough about it, your vehicle could be damaged. 6-2