Pontiac 1993 Grand Am Owner's Manual page 203

3
Gasolines for Cleaner Air
Your use of gasoline with detergent
additives will help prevent deposits from
forming in your engine and fuel system.
That helps keep your engine in tune and
your emission control system working
properly. It's good for your vehicle, and
you'll be doing your part for cleaner air.
Many gasolines are now blended with
materials called oxygenates. General
Motors recommends that you use
gasolines with these blending materials,
such as MTBE and ethanol. By doing
so, you can help clean the air, especially
in those parts of the country that have
high carbon monoxide levels.
In addition, some gasoline suppliers are
now producing reformulated gasolines.
These gasolines are specially designed
to reduce vehicle emissions. General
Motors recommends that you use
reformulated gasoline. By doing so, you
can help clean the air, especially in
those parts of the country that have high
ozone levels.
You should ask your service station
operators if their gasolines contain
detergents and oxygenates, and if they
have been reformulated to reduce
vehicle emissions.
Fuels in Foreign Countries
If you plan on driving in another
country outside the U.S. or Canada,
unleaded fuel may be hard to find.
Do not use leaded gasoline. If you use
even one tankful, your emission controls
won't work well or at all. With
continuous use, spark plugs can get
fouled, the exhaust system can corrode,
and your engine oil can deteriorate
quickly. Your vehicle's oxygen sensor
will be damaged. All of that means
costly repairs that wouldn't be covered
by your warranty.