2011 Chevrolet Cruze Owner's Manual - Page 235

Driving and Operating . 9-39 An object was hanging out of the trunk during the last drive cycle. Once the object is removed, URPA will return to normal operation. The vehicle's bumper is damaged. Take the vehicle to your dealer to repair the system. Other conditions may affect system performance, such as vibrations from a jackhammer or the compression of air brakes on a very large truck. Fuel Use of the recommended fuel is an important part of the proper maintenance of this vehicle. To help keep the engine clean and maintain optimum vehicle performance, we recommend the use of gasoline advertised as TOP TIER Detergent Gasoline. Look for the TOP TIER label on the fuel pump to ensure gasoline meets enhanced detergency standards developed by auto companies. A list of marketers providing TOP TIER Detergent Gasoline can be found at www.toptiergas.com. . . 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 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.