1998 Chevrolet Corvette Owner's Manual - Page 248

CAUTION: (Continued) - Be sure you have sufficient knowledge, experience, the proper replacement parts and tools before you attempt any vehicle maintenance task. Be sure to use the proper nuts, bolts and other fasteners. "English" and "metric" fasteners can be easily confused. If you use the wrong fasteners, parts can later break or fall off.You could be hurt. Adding Equipment to the Outside of Your Vehicle Things you rnight to the outside of your vehicle can add affect the airflow aroundit. This may cause wind noise and affect windshieldwasher performance. Check with equipment to the outside of your dealer before adding your vehicle. 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 performance and engine protection. Gasolines meeting the AAMA specification could provide improved driveability and emission control system protection compared to other gasolines. Be sure the posted octane for premium is atleast 91 (at least 89 for middle grade and 87 for regular). If the heavy knocking octane is less than 87, you may get a noise when you drive. If it's badenough, it candamage your engine. If you're using fuel rated at the recommended octane or higher and you 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 pinging. It's the heavy, constant knock that means you have a problem. If your vehicle is certified to meet California Emission Standards (indicated on the underhood emission control label), it isdesigned to operate on fuels that meet California specifications. If such fuels are not available in states adopting California emissions standards, your f Fuel Use premium unleadedgasoline rated at 91 octane or higher for best performance. You may use middle grade or regular unleadedgasolines, but your vehicle may not accelerate as well. 6-3