Visually check the spark plug wires for burns cuts, or breaks in the insulation. Check the boots and the nipples on the distributor cap and/or coil. Replace any damaged wiring; cracked or shorted spark plug wires can short to ground, and cause a -miss- when the engine is running.
Measure the resistance of the spark plug wire using an ohmmeter. On 4.3L engines, it should be 1,200-1,500 ohms per foot. On all other engines, the wires should be between 397- and 1,337 ohms.
Removal & Installation
- Before servicing the vehicle, refer to the Precautions section.
- Label each spark plug wire and make a note of its routing.
- Twist, then pull the spark plug wire from the spark plug and then from the coil pack.
- If replacing the spark plug wires, match the old wire with an appropriately sized wire in the new set.
- Lubricate the boots and terminals with dielectric grease and install the wire on the coil pack. Make sure the wire snaps into place.
- Route the wire in the exact path as the original and connect the wire to the spark plug.
- Repeat the process for each remaining wire.