ENGINE MISSFIRE-HARD THROTTLE 2.0 TURBO/ REVISED PLUG GAP

ENGINE MISFIRE UNDER HARD THROTTLE, I.E., TURBO BOOST

1987 2.OL LT3 (VIN CODE M) ENGINE

Some engines may misfire under hard throttle, such as during turbo boost conditions. The miss is caused by excessively high ignition system demand voltage of the high gap (.060") spark plug and combustion conditions.

The misfire is repairable by installing a .035" gap spark plug with service P/N 5613820 (R42XLS, a previous 1986 turbo spark plug).

For future spark plug service on this vehicle, non-destructible peel-off labels are included with this bulletin. This reference label should be placed on the same mounting surface as the current vehicle emission control information, "Tune-Up" label.

Use applicable labor operations and labor 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.