Fuel - Chevrolet 1994 Blazer Owner's Manual

Fuel
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 regular unleaded gasoline rated at 87 octane or higher. With the 4.3L
(Code W) engine, use premium unleaded gasoline rated at 91 octane or
higher for high power performance, when towing a trailer or with a high
payload requirement. But when operating with a light load as a normal
condition, you may use middle grade or regular unleaded gasolines.
The gasoline you use should meet specifications ASTM D48 14 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 is at least 9 1 for premium, 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 it. 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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