1993 Buick Riviera Owner's Manual - Page 219

Fuel Use regular unleaded gasoline rated at octane or 87 higher: It should meet specifications ASTM D4814 in the U.S. and CGSB 3.5.92 in Canada. These fuels should have the proper additives,so you should not have to add anything the fuel. to Use regular unleaded gasoline rated at octane or 87 higher. It should meet specifications ASTM D4814 in the U.S. and CGSB 3.5-92 in Canada. These fuels should havethe proper additives,so you should not have to add anything to fuel. the What about gasoline with blending materials that contain oxygen, suchas MTBE or alcohol? no MTBE is "methyl tertiary-butyl ether." Fuel that is more than 15% MTBE fine for your vehicle. is 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 U.S. and Canada,it's easy to be sure you get the right kindof gasoline (unleaded). You'll see "UNLEADED" right onthe pump. And only unleaded nozzles willfit into your vehicle'sfiller neck. If Be sure the posted octane is at least 87. the octane is less than 87, you may get a heavy knocking noise when it you drive. If it's bad enough, can damage your engine. If you're using fuel rated 87 octane or higher and you at still hear heavy knocking, your engine needs service. But don't worry if you hearlittle pinging noise when a you're accelerating or driving a hill. That's normal, up and you don't have to buy a higher octane fuel get rid to of pinging. It's the heavy, constant knock that means you have a problem. 217