General Motors recommends that owners familiarize themselves with the information in their vehicle owner's manual pertaining to recommended fuels.
Some vehicle owners currently using unleaded fuel may experience a condition such as cold start stall and/or reduced cold engine performance.
It is imperative that technicians ensure the vehicle's basic engine, controls and systems are performing properly. If all engine controls and systems are performing properly, it is recommended that the vehicle owner change to a different brand of regular grade 87 octane unleaded fuel. It may require several tanks full of a different brand of fuel before the condition improves.
Use of fuels with an octane rating higher than 87, unless specified in the vehicle owner's manual, is not required. Use of premium grade unleaded fuel, 91 octane or higher, will not enhance the vehicles cold start quality and/or cold engine performance.
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.