1996 Chevrolet Tahoe Owner's Manual - Page 256

Fuel (Gasoline Engine) If your vehicle hasa diesel engine, see"Diesel Fuel Requirements and Fuel System" in the Diesel Engine Supplement. For vehicles with gasoline engines, please read this. Use regular unleaded gasoline rated at 87 octane or higher. At a minimum, it should meet specifications ASTM D4814 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 is at least 87. If the octane is less than 87, you may get a heavy knocking noise when you drive. If it's bad enough, it can damageyour engine. If you're using fuel rated at 87 octane or higher you and still hear heavy knocking, your engine needs service. But don't worryif 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 toget 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 onthe underhood tune-up label), it is designed to operate on,fuelsthat meet California specifications. If such fuels arenot available in states adopting California emissionsstandards, your vehicle will operate satisfactorily on fuels meeting federal specifications, but emission control system performance may be affected. The malfunction indicator lamp on your instrument panel may turn on and/or your vehicle may fail a smog-check test. If this occurs, return to your authorized GM dealer fordiagnosis to determine the cause of failure. In the event it is determined that the cause of the condition is the type of fuels used, repairs may not be covered by your warranty. a In Canada, somegasolines contain an octane-enhancing additive calledMMT. If you use such fuels, your emission controlsystem performance may deteriorate and the malfunction indicator lamp on your instrument panel may turn on. If this happens, return to your authorized GM dealer forservice. 6-3