2013 Chevrolet Impala Owner Manual - Page 211

Driving and Operating knock, might be heard when driving. If this occurs, use a gasoline rated at 87 octane or higher as soon as possible. If heavy knocking is heard when using gasoline rated at 87 octane or higher, the engine needs service. 9-31 Gasoline Specifications At a minimum, gasoline should meet ASTM specification D 4814. Some gasolines contain an octane-enhancing additive called methylcyclopentadienyl manganese tricarbonyl (MMT). We recommend against the use of gasolines containing MMT. See Fuel Additives on page 9‑32. Vehicles that have a yellow fuel cap can use either unleaded gasoline or ethanol fuel containing up to 85% ethanol (E85). See Fuel E85 (85% Ethanol) on page 9‑33. For all other vehicles, use only the unleaded gasoline described under Recommended Fuel on page 9‑31. states adopting California Emissions Standards, the vehicle will operate satisfactorily on fuels meeting federal specifications, but emission control system performance might be affected. The malfunction indicator lamp could turn on and the vehicle might fail a smog‐check test. See Malfunction Indicator Lamp on page 5‑14. If this occurs, return to your authorized dealer for diagnosis. If it is determined that the condition is caused by the type of fuel used, repairs might not be covered by the vehicle warranty. Fuels in Foreign Countries Never use leaded gasoline or any other fuel not recommended in the previous text on fuel. Costly repairs caused by use of improper fuel would not be covered by the vehicle warranty. Recommended Fuel Use regular unleaded gasoline with a posted octane rating of 87 or higher. If the octane rating is less than 87, an audible knocking noise, commonly referred to as spark California Fuel Requirements If the vehicle is certified to meet California Emissions Standards, it is designed to operate on fuels that meet California specifications. See the underhood emission control label. If this fuel is not available in