1995 Pontiac Firebird Owner's Manual - Page 236

Fuel 3.4L L32 (Code S) and 3.8L L36 (CodeK) The 8th digit your vehicle identification number of (VIN) shows the code letter your engine.You will for find the VIN at the top of your instrument panel. left (See "Vehicle Identification Number" in the Index.) Use regular unleaded gasoline rated 87 octane or at 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, you should not so have to add anything to the fuel. In the United States and Canada, it's easy to be sure you get the right kind gasoline (unleaded). You'll of see UNLEADED right on the pump. And only unleaded nozzles will fit into your vehicle's filler neck. of pinging. It's the heavy, constant knock means that you have a problem. What about gasoline with blending materials that contain oxygen (oxygenates), such MTBE or alcohol? as MTBE is "methyl tertiary-butyl ether." Fuel that is no more than 15% MTBE fine for your vehicle. is Ethanol is ethyl or grain alcohol. Properly-blendedfuel that 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 system and also damage plastic Be sure the posted octane is at least 87. Ifoctane is the be less than 87, you may get a heavy knocking noise when and rubber parts. That damage wouldn't you drive. If it's bad enough, damage your engine. it can covered under your warranty. And even 5% or at less, there must be "cosolvents" and corrosion If you're using fuel rated at octane or higher and you 87 preventers in this fuel to help avoid these still hear heavy knockmg, your engine needs service. problems. But don'tworry if you hear a little pinging noise when you're accelerating or driving a hill. That's normal, up and you don'thave to buy a higher octane to get rid fuel 6-3