1994 Pontiac Firebird Owner's Manual - Page 186

H Fuel The 8th digit of your Vehicle Identification Number (VIN) shows You the code letter for your engine. will find theVIN at the top left of your instrument panel. (See "Vehicle Identification Number" in the Index.) ' 1 3.4L L32 (Code S) 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 haveto add anything to: the fuel. In the U.S. and Canada, it's easy to be sure you get the right kind of giisoline (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 knochng noise when you drive. If it's bad enough, it can damage your engine. If you're using fuel ratedat 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 acceleratingor 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. 5 7 LT1 (Code P) .L Use premium unleaded gasoline rated at 91 octane or higher. You may use middle grade or regular unleaded gasolines, but your vehicle may not accelerate as well. The gasoline you use 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 haveto add anything to the fuel. In the U.S. and Canada, it's easyto be sure you get the right lund 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 for premium is at least 91 (at least 89 for middle grade and 87 for regular). If the octane is less than 87, you may get a heavy knocking noise when you drive. If it's badenough, it can damage your engine. 91 If you're using fuel rated at octane or higher and you still hear heavy knocking, your engine needs service. But don't worry if you hear a littlepinging noise when you're accelerating or driving up a hill. That's normal and you don't have to buy a higher octane fuelto get rid of pinging. It's the heavy,constant knock that means you have a problem. All Engines 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 than15% MTBB is fine for your vehicle. Ethanol is ethyl or grainalcohol. Properly-blended fuel that is no more than 10% ethanol is fine for your vehicle. Methanol is methyl or woodalcohol. 185 ...