To replace the ignition coil on most models, disconnect the negative
Battery Cable and locate the ignition coil. If necessary, unscrew the mounting bracket bolts to remove the coil. Disconnect the wires from the coil's terminals. Use an ohmmeter to test the resistance at the primary terminal and ground, the positive and negative primary terminals, and the negative primary and high voltage terminals. If any tests fail, replace the coil. To do so, disconnect the wires from the coil's terminals, remove the mounting bracket bolts and the coil. Install the new coil in reverse order. For 2000 and later inline six-cylinder models, remove and clean the ignition coil rail assembly. Check for damage and test the coil primary resistance at terminals 2 and 1, 2 and 3, and 2 and If the resistance is out of range or if there's damage, replace the entire assembly. To replace, remove the assembly, disconnect the electrical connector, and install the new assembly, ensuring all spark plug boots are properly seated. Secure with mounting bolts and reconnect the electrical connector.