Pontiac 1994 Grand Am Owner's Manual page 173

Service
&
Appearance Care
Fuel
2.3L High Output Quad 4 Engine
(Code A):
The 8th digit of your Vehicle
Identification Number (VIN) shows the
code letter for your engine. You will find
the VIN at the top left of your instrument
panel. (See "Vehicle Identification
Number" in the Index.)
Use premium unleaded gasoline rated at
91 octane or higher. You may use middle
grade or regular unleaded gasolines, but
your vehicle may not accelerate as well.
The gasoline you use should meet
specifications ASTM D4814 in the U.S.
and CGSB 3.5-92 in Canada. These fuels
should have the proper additives, so you
should not have to add anything to the
fuel.
In the U.S. and Canada, it's easy to be
sure you get the right kind of gasoline
(unleaded). You'll see "UNLEADED'
right on the pump. And only unleaded
nozzles will fit into your vehicle's filler
neck.
Be sure the posted octane for premium is
at least 91 (at least 89 for middle grade
and 87 for regular). If the octane is less
than 87, you may get a heavy knocking
noise when you drive. If it's bad enough,
it can damage your engine.
If you're using fuel rated at 91 octane or
higher and you still hear heavy knocking,
your engine needs service. But don't
worry if you hear a little pinging noise
when you're accelerating or driving up a
hill. That's normal and you don't have to
buy a higher octane fuel to get rid of
pinging. It's the heavy, constant knock
that means you have a problem.
What about gasoline with blending
materials that contain oxygen
(oxygenates), such as MTBE or alcohol?
MTBE is "methyl tertiary-butyl ether.''
Fuel that is no more than 15% MTBE is
Fine for your vehicle.
Ethanol is ethyl or grain alcohol.
Properly-blended fuel that is no more
than 10% ethanol is fine for your vehicle.
Methanol is methyl or wood alcohol.
NOTICE:
Fuel that is more than
5%
methanol
is bad for your vehicle. Don't use it.
It can corrode metal parts in your
fuel system and also damage plastic
and rubber parts. That damage
wouldn't be covered under your
warranty. And even at 5% or less,
there must be "cosolvents" and
corrosion preventers in this fuel to
help avoid these problems.
.
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