Fuel - Chevrolet 1993 Astro Passenger Owner's Manual

Service & Appearance Care
NOTICE
I -
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 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 is at least 91 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.
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