To check the ignition coil, begin by turning off the ignition and then unfastening the electrical connectors from the coil. To ensure that an ignition coil is performing at its best, connect an ohmmeter between the positive (+) and negative (-) terminals of the coil to measure primary resistance. As recommended in specifications, the resistance should be in a specific range, otherwise replace it. Afterward, link one terminal of your ohmmeter to the secondary terminal (where spark plug wires attach) and on the other end of your meter link to ground as shown below to measure secondary resistance of coil. As recommended in specifications, the resistance should be in a specific range; if not replace it. To do this, start by disconnecting battery's cable from the negative terminal followed by removing an electrical connector for ignition and high tension wire (coil-to-cap) from this last device. At last, remove its attachments on engine where there was mounting bolts before completely unfastening it from inside engine compartment. In order to reverse removal procedure with some additional steps for installation: coat silicone dielectric compound throughout entire inner surface of rubber boot before putting back spark plug wire connector into ignition coil.