CHECKING AND REPLACING SPARK PLUG WIRES
See Figures 1 and 2
Your car is equipped with an electronic ignition system which utilizes 8mm wires to conduct the hotter spark produced. The boots on these wires are designed to cover the spark plug cavities on the cylinder head.
Inspect the wires without removing them from the spark plugs, distributor cap or coil. Look for visible damage such as cuts, pinches, cracks or torn boots. Replace any wires that show damage. If the boot is damaged, it may be replaced by itself. It is not necessary to replace the complete wire just for the boot.
To remove the wire, grasp and twist the boot back and forth while pulling away from the spark plug. Use the specialized pliers mentioned earlier in this section, if available. For 3.0L and 3.2L SHO vehicles, in order to remove the wires from the ignition coil, squeeze the locking tabs of the ignition wire retainer and use a gentle twisting/pulling motion.
Always coat the terminals of any wire that is removed or replaced with a thin layer of silicone dielectric compound (D7AZ-19A331-A or equivalent).
When installing a wire, be sure it is firmly mounted over or on the plug, distributor cap connector or coil terminal.
Every 30,000-45,000 miles (48,000-72,000 km), the resistance of the wires should be checked using an ohmmeter. Wires with excessive resistance will cause misfiring and may make the engine difficult to start in damp weather.
To check resistance, remove the distributor cap, leaving the wires in place. Connect one lead of an ohmmeter to an electrode within the cap; connect the other lead to the corresponding spark plug terminal (remove it from the spark plug for this test). Any wire with a resistance over 7,000 ohms per foot of wire should be replaced.