The vehicles and engine combinations indicated above may experience a rough idle condition (at idle or off-idle) that is generated by a lean mixture. Normal service manual diagnostic procedure should be followed to isolate the cause of the lean mixture.
The EFE isolator/gasket below the carburetor should be checked for vacuum leakage, contributing to the lean condition. If the EFE isolator/gasket is identified as the vacuum leak source, then the isolator/gasket should be replaced per service manual procedure.
The EFE isolator/gasket (P/N 14018761) is available from GMSPO on their "Target Program" and is covered by GM's 5 yr/50,000 mile emission warranty.
Use applicable labor operation and time.
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.