Some owners of vehicles with multi-port injection systems may have experienced impaired driveability resulting from deposits forming on fuel injectors. The symptoms include a rough idle and decreased acceleration. When the problem first occurred, few gasolines contained detergent additives which could prevent the deposit buildup, and even fewer could remove the deposits from fouled injectors.
About a year ago, General Motors and other auto companies asked gasoline suppliers to provide gasolines containing sufficient concentrations of appropriate detergents to prevent port-fuel injector deposits.
The response to the auto industry's requests has been very encouraging. It now appears not only that all major brands are treated with detergent additives, but also that many independent brands either are now, or soon will be treated. This includes those brands selling ethanol-containing gasoline, for which the ethanol has been treated with a detergent additive.
Because the number of brands now treated with detergents is becoming so extensive, General Motors is no longer publishing a list of brands advertised to contain the needed detergents. Instead, customers should be urged to purchase fuel from any gasoline marketer who states, at the point of purchase or through media advertising, that the gasoline contains a sufficient level of detergent additives to prevent port fuel injector deposits or remove them from fouled injectors. Customers properly informed by the claims of gasoline suppliers or marketers will be in a position to prevent the unnecessary fouling which may result from the use of a gasoline with ineffective or no detergent additives. While these claims are not based on data generated by General Motors, we have no reason to doubt their truth.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.