Ford Thunderbird Owner's Manual page 234

To make sure that the catalytic converter and the
other emission control parts continue to work
properly:
Use only unleaded fuel.
Avoid running out of fuel.
Do not turn off the ignition while your
vehicle is moving, especially at high speeds.
Do not push start your vehicle.
Have the services listed in the Maintenance
Schedule booklet performed according to the
specified schedule. The scheduled
maintenance services are required because
they are considered essential to the life and
performance of your vehicle and to its
emissions system.
In general, maintenance, replacement, or service
of the emissions control devices or systems in
your new Ford Motor Company vehicle or
engine may be performed at your expense by
any automotive repair establishment or
individual using automotive parts equivalent to
those which your vehicle or engine was
originally equipped.
Ford strongly recommends the use of genuine
Ford replacement parts. If other than Ford or
Motorcraft parts or Ford authorized
remanufactured parts are used for maintenance
replacements or for the service of components
affecting emission control, such non-Ford parts
should be equivalent to genuine Ford Motor
Company parts in performance and durability. It
is the owner's responsibility to determine the
equivalency of such parts. Please consult your
warranty booklet for complete warranty
information.
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