Saturn 2010 AURA Hybrid - Manual (Page 264)

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.
Gasoline Octane
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.
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