Toyota Lexusc Owner's Handbook Manual page 653

ENGINE
Octane rating
Select Octane Rating 87 (Research Octane Number 91) or
higher. For improved vehicle performance, the use of
premium unleaded gasoline with an Octane Rating of 91
(Research Octane Number 96) or higher is recommended.
Use of unleaded fuel with an Octane Rating or Research
Octane Number lower than stated above will cause persistent
heavy knocking. If it is severe, this will lead to engine damage.
If your engine knocks...
If you detect heavy knocking even when using the
recommended fuel, or if you hear steady knocking while
holding a steady speed on level roads, consult your Lexus
dealer.
However, occasionally, you may notice light knocking for a
short time while accelerating or driving up hills. This is normal
and there is no need for concern.
Gasoline containing detergent additives
Lexus recommends the use of gasoline that contains
detergent additives to avoid build-up of engine deposits.
However, all gasoline sold in the U.S. contains detergent
additives to keep clean and/or clean intake systems.
634
Quality gasoline
Automotive manufacturers in the U.S., Europe and Japan
have developed a specification for quality fuel named
World-W ide Fuel Charter (WWFC) that is expected to be
applied world wide. The WWFC consists of four
categories that depend on required emission levels. In the
U.S., category 4 has been adopted. The WWFC improves
air quality by providing for better emissions in vehicle
fleets, and customer satisfaction through better vehicle
performance.
Cleaner burning gasoline
Cleaner burning gasoline,
gasoline that contains oxygenates such as ethanol or
MTBE is available in many areas.
Lexus recommends the use of cleaner burning gasoline and
appropriately blended reformulated gasoline. These types of
gasoline provide excellent vehicle performance, reduce
vehicle emissions, and improve air quality.
including reformulated