1994 Oldsmobile Bravada Owner's Manual - Page 169

Fuel Use regular unleaded gasoline rated at 87 octane or higher. Use premium unleaded gasoline rated at 91octane or higher for high power performance, when towing a trailer or with a high payload requirement. But when operating with a light load as a normal condition, you may use middle grade or regular unleaded gasolines. The gasoline you useshould meet specifications ASTM D4814 in the U.S. and CGSB3.5-92 in Canada. These fuels should have the proper additives, so you should not have to add anything to the fuel. In the U.S. 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 fitinto your vehicle's filler neck. Be sure the posted octane is at least 91 for premium, 89 for middle gradeand 87 for regular.If the octane is lessthan 87, you may geta heavy knocking noise when you drive. If it's bad enough, it can damage your engine. If you're using fuel rated at 91 octane or higher 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 a hill. That's normal, and you don't have to buy a higher octane fuel to get rid of it. It's the heavy, constant knock that means you have a problem. What about gasoline with blending materials that contain oxygen (oxygenates), such asMTBE or alcohol? MTBE is "methyl tertiary-butylether." Fuel that is no more than 15%MTBE is fine for your vehicle. Ethanol is ethyl or grain alcohol. Properly-blended fuelthat is no more than 10% ethanol is fine for your vehicle. Methanol is methyl or wood alcohol. NOTICE: Fuel that is more than 5% methanol is bad for your vehicle. Don't use it. It can corrode metal parts in your fuel systemand also damage plastic 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 help avoid these problems. GasoUnes forCleaner Air Your use of gasoline with deposit control additives will help prevent deposits from formingin your engine and fuel system. That helps keep your engine in tune and your emission control system working properly. It's good for your vehicle, you'll be and doing yourpart for cleaner air. Many gasolinesare now blended with oxygenates. General Motors 163