1997 Pontiac Bonneville Owner's Manual - Page 256

Adding Equipment to the Outside of Your Vehicle Things youmight add to the outside your vehicle can of affect the airflow aroundit. This may cause wind noise and affect windshield washer performance. Check with your Pontiacdealer before adding equipment to the outside of your vehicle. If you have the 3800 Supercharged engine (VIN Code l), use premium unleaded gasoline rated at 91 octane or higher. With the3800 Supercharged engine, in an emergency, you may be able to use a lower octane -- as low as 87 -- if heavy knocking does not occur. If you are using 91 or higher octane unleaded gasoline and you still hear heavy knocking,your engine needs service. At a minimum, the gasoline you use should meet specifications ASTM D48 14 in the United States and CGSB 3.5-M93 in Canada. Improved gasoline specifications have been developed by the American Automobile Manufacturers Association (AAMA)for better vehicle performanceand engine protection. Gasolines meeting theAAMA specification could provide improved driveability and emission control system protection compared to othergasolines. 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 bad enough, it can damage your engine. The 8th digitof your vehicle identification number (VIN) shows the code letter your engine. You will for find the VIN at the top left your instrument panel. of (See "Vehicle IdentificationNumber" in the Index.) If you have the 3800 engine (VIN Code K), use regular 87 unleaded gasoline rated at octane or higher. If you're using fuel rated at the recommended octane or higher and you still hear heavy knocking, your engine needs service. But don't worryif you hear alittle pinging noise when you're accelerating or drivingup a hill. That's normal, and you don't haveto buy a higher octane fuel to get rid of pinging. It's the heavy, constant knock that means you have a problem.