catalytic converter Lexus ES300 1997 Service Procedures And Specifications: Engine

ENGINE
198
FUEL
Fuel type
Your vehicle must use only unleaded gasoline.
To help prevent gas station mixups, your Lexus has a smaller
fuel tank opening. The special nozzle on pumps with
unleaded fuel will fit it, but the larger nozzle on pumps with
leaded gas will not.
NOTICE
Do not use leaded gasoline. Use of leaded gasoline
will cause the three±way catalytic converter to lose
its effectiveness and the emission control system to
function improperly. Also, this can increase
maintenance costs.
Octane number
Select Research Octane Number 91 (Octane Rating 87)
or higher. For improved vehicle performance, the use of
premium unleaded gasoline with a Research Octane
Number of 96 (Octane Rating 91) or higher is
recommended.
Use of unleaded fuel with an octane number or rating lower
than stated above will cause persistent heavy knocking. If
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, now and then, you may notice light knocking for a
short time while accelerating or driving up hills. This is no
cause for concern.
Gasolines containing detergent additives
Lexus recommends use of gasolines that contain
detergent additives to avoid build±up of engine
deposits.
For further details, ask your Lexus dealer or a local gasoline
retailer.
Gasolines containing MTBE
Gasolines that contain MTBE (Methyl Tertiary±Butyl
Ether) are available on the market. If you use a gasoline
mixed with MTBE, make certain that it does not contain
more than 15% of MTBE.
If the use of gasolines containing MTBE causes poor
drivability and/or poor fuel economy, you should stop using
them.