2010 Cadillac CTS Owner's Manual - Page 289

Driving and Operating 8-49 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. The VIN is at the top left of the instrument panel. See Vehicle Identification Number (VIN) on page 11‑1. Recommended Fuel If the vehicle has a V6 engine, 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. If the vehicle has the 6.2L V8 engine (VIN Code P), use premium unleaded gasoline with a posted octane rating of 91 or higher. For best performance, use premium unleaded gasoline with a posted octane rating of 93. In an emergency, you can use regular The 8th digit of the Vehicle Identification Number (VIN) shows the code letter or number that identifies the vehicle's engine.