1995 Buick Regal Owner's Manual - Page 211

Fuel Use regular unleaded gasoline rated at 87 octane or higher. It should meet specifications ASTM 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 anything tothe fuel. What about gasolinewith blending materials that contain oxygen (oxygenates), such as MTBE or alcohol? MTBE is "methyl tertiary-butyl ether." Fuel that is no more than 15% MTBE is fine for your vehicle. Ethanol is ethyl or grain alcohol. Properly-blended fuel that is no more than 10% ethanol is fine for your vehicle. Methanol is methyl or wood alcohol. In the United States and Canada, it's easy to be sure you get the right kind of gasoline (unleaded).You'll see UNLEADED right on the pump. And only unleaded nozzles will fit into your vehicle's filler neck. Be sure the posted octane is at least 87. If the octane is less than 87, you may get a heavy knocking noise when you drive. If it's bad enough, it can damage your engine. If you're using fuel rated at 87 octane orhigher and you still hear heavy knocking, your engine needs service. But don't worry if you hear a little pinging noise when you're accelerating or driving up hill. That's normal, a and you don't have to buy a higher octane fuel to get rid of pinging. It's the heavy, constant knock that means you have a problem. I NOTICE: Fuel that is more than 5% methanol is bad for your vehicle. Don't use It can corrode metal it. parts in your fuel system also damage plastic and and rubber parts. That damage wouldn't be covered under your warranty. And even at 5% or less, there must be "cosolvents" and corrosion preventers in this fuel to avoid these help problems.