For 1990-2009 cars

# ROUGH IDLE,SURGE,MISFIRE AND / OR POOR PERFORMANCE

1985/86 6000, FIREBIRD, AND FIERO MODELS WITH 2.8L-V6 MPFI ENGINES (VIN CODES W, S, & 9)

A condition may be encountered described as engine misfire, rough idle, stumble, surge, chuggle, and/or poor performance. In addition to checking the components and systems outlined in section 6E3 of the service manual (fuel injectors, TPS switch, MAF sensor, oxygen sensor, etc.), carefully check to the condition of the spark plug wires.

A condition exists whereby spark plug wire secondary current can form a carbon track on the inside of the spark plug boot and arc to the metal shield that surrounds the spark plug. The condition is caused by improper assembly of the spark plug boot terminal to the spark plug terminal end during engine assembly.

To repair the condition, the spark plug wire and spark plug should both be changed and the boot firmly seated onto the terminal end of the plug to ensure that the condition does not recur.

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.