KNOCK / MISS / SURGE SPARK PLUG UPDATE

Some 1981 and 1982 vehicles with the LE9 engine may experience preignition or poor performance under moderately severe operating conditions. As a result of the preignition, the ESC retards the spark timing giving a marked loss of power and a noticeable reduction in performance. The preignition may not be corrected by the spark retard, and continued operation under these conditions could cause internal engine damage.

To reduce the probability of this occurrence, the spark plugs should be changed to a colder heat range.

Install R44TS plugs in place of the original R45TS plugs.

Use applicable labor operation.

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.