1994 Pontiac Grand Am Owner's Manual - Page 172

Use regular unleaded gasoline rated at 87 octane or 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 toadd 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 fit into your vehicle's filler neck. Be sure the posted octane is atleast 87. If the octane is less than 87, you may get a heavy knocking noise when you drive. If it's bad enough,-itcan damage your engine. If you're using fuel rated at 87 octane or higher and you still hear heavy knoclung, 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 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? MTBE is "methyl tertiary-butyl ether.'' Fuel that is no more'than 15% MTBE is fine foryour vehicle. Ethanol is ethylor grain alcohol. Properly-blended fuel that is no more than 10%ethanol is fine for your vehicle. Methanol is methyl or wood alcohol. I Fuel !.3L Quad OHC andQuad 4 Engines Codes 3 and D) and 3.1L V6 Engine Code M): 'he 8th digit of your Vehicle dentification Number (VIN) shows the :ode letter for your engine.You will find he VIN at the top left of your instrument )anel. (See "Vehicle Identification Vumber" in the Index.) NOTICE: Fuel that is more than 5% methanol is bad for your vehicle. Don't use it. It can corrode metal.parts in yohs fuel system and also, damage plastic and rubber parts. That damage wouldn't be covered under your warranty. And evenat 5% or less, there must be "cosolvents" and corrosion preventers in this fuel to help avoid these problems. 171 ...