Envoy 2WD V6-4.3L VIN W (1998)
Fuel: Description and Operation
Fuel (Regular)
The following information appears in the General Motors owners manual for this vehicle.
Use regular unleaded gasoline rated at 87 octane or higher. At a minimum, it should meet specifications ASTM D4814 in the United States and CGSB
3.5-M93 in Canada. Improved gasoline specifications have been developed by the American Automobile Manufacturers Association (AAMA) for better
vehicle performance and engine protection. Gasolines meeting the AAMA specification could provide improved driveability and emission control system
protection compared to other gasolines.
Be sure the posted octane is at least 87. 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 87 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.
If your vehicle is certified to meet California Emission Standards (indicated on the underhood tune-up label), it is designed to operate on fuels that meet
California specifications. If such fuels are not available in states adopting California emissions standards, your vehicle will operate satisfactorily on fuels
meeting federal specifications, but emission control system performance may be affected.
The malfunction indicator lamp on your instrument panel may turn on and/or your vehicle may fail a smog-check test. If this occurs, return to a qualified
service outlet for diagnosis to determine the cause of failure. In the event it is determined that the cause of the condition is the type of fuels used, repairs
may not be covered by your warranty.
Some gasolines that are not reformulated for low emissions contain an octane-enhancing additive called methylcyclopentadienyl manganese tricarbonyl
(MMT); ask your service station operator whether or not his fuel contains MMT General Motors does not recommend the use of such gasolines. If fuels
containing MMT are used, spark plug life may be reduced and your emission control system performance may be affected. The malfunction indicator
lamp on your instrument panel may turn on. If this occurs, return to a qualified service outlet for service.
To provide cleaner air, all gasolines in the United States are now required to contain additives that will help prevent deposits from forming in your
engine and fuel system, allowing your emission control system to function properly. Therefore, you should not have to add anything to the fuel. In
addition, gasolines containing oxygenates, such as ethers and ethanol, and reformulated gasolines may be available in your area to help clean the air.
General Motors recommends that you use these gasolines if they comply with the specifications described earlier.
Notice: Your vehicle was not designed for fuel that contains methanol. 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.
