For 1990-2009 cars

# ENGINE MISS OR RUNS ROUGH (REPLACE SPARK PLUG WIRES)

#### SUBJECT: ENGINE MISS ROUGHNESS (REPLACE SPARK PLUG WIRES)

#### VEHICLES AFFECTED: 1991 CADILLAC "C" CAR WITH 4.9L ENGINE (VIN CODE 'B')

Some 1991 DeVilles and Fleetwoods built between VIN 228800 and 229200 may experience a condition of an engine miss roughness.

This condition may be caused by abrasion of the number 2 and 4 spark plug wires. The abrasion may be caused by contact between the nylon mesh that covers the heater hose and an unshielded plug wire.

To identify and correct this condition use the following procedure:

1. Inspect spark plug wire numbers 2 and 4 for any signs of abrasion. Replace any abraded wires.

2. Order P/N 12125347, convoluted conduit, for installation on the number 2 and 4 spark plug wires. It is packaged in a 15' roll.

3. Install a 105mm length of convoluted conduit, P/N 12125347, onto the number 4 spark plug wire. It should completely cover the wire from the spark plug boot to the spark plug wire retainer.

4. Install a 145mm length of convoluted conduit, P/N 12125347, onto the number 2 spark plug wire. It should completely cover the wire from the spark plug boot to the spark plug wire retainer.

For vehicles repaired under warranty use: Labour time .6 hour.

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.