At every tune-up/inspection, visually check the spark plug cables 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.
Every 50,000 miles (80,000 Km) or 60 months, the resistance of the wires should be checked with an ohmmeter. Wires with excessive resistance will cause misfiring, and may make the engine difficult to start in damp weather.
Spark plug wire resistance may be checked either through the distributor cap or individually. To check individually, remove the wire from both the distributor cap and spark plug. Connect an ohmmeter lead to each end of the wire to measure resistance. The vehicle manufacturer-s specification for plug wire resistance is 4,150-5,610 ohms/ft. (13,600-18,400 ohms/meter). Move the wire to check for intermittent breaks inside of the wire.
To check through the distributor cap, remove spark plug wires from the spark plugs and remove the distributor cap from the distributor, leaving the plug wires attached. Connect one ohmmeter lead to the end of the wire, and the other lead to the corresponding terminal inside of the distributor cap. If resistance is above normal, inspect the plug wire to distributor cap connection. If the connection is good, check the plug wire separately and replace if needed.