For 1999 through 2005 models with four-cylinder engines, start by removing the coils from the engine. Connect an ohmmeter between the two secondary terminals of each coil to check the secondary resistance. If any reading differs substantially, replace that coil. Use jumper wires to connect two 1.5-volt batteries in series to create a 3-volt power supply. Connect the negative end of the power supply to the middle terminal of the three-wire coil wiring connector. Connect an ohmmeter between the number two and three terminals and take a reading. There should be nearly infinite resistance. Now connect the positive end of the power supply to terminal one and read the resistance again. If any of the above readings vary substantially, replace the coil. For V6 engines, disconnect the spark plug wires from the coil pack and the primary wiring connector. Connect an ohmmeter between the first two spark plug terminals on the coil to check the secondary resistance. Repeat this procedure for the middle two terminals and the last two. Connect the ohmmeter between terminals 1 and 2 of the wiring connector to check the primary resistance for cylinders 3 and 6. Repeat this procedure between terminals 2 and 4 for cylinders 1 and 4, and between terminals 2 and 3 for cylinders 2 and 5. For 2006 and later models, remove the coils from the engine and connect an ohmmeter between the two primary terminals of each coil to check the readings. Compare the readings with the specifications and replace any coil that differs greatly. If in doubt, try swapping the coil to another cylinder. For replacement, start by disconnecting the cable from the negative battery terminal and removing the engine cover. Disconnect the electrical connector from the ignition coils and remove the mounting bolts. On four-cylinder models, also disconnect the spark plug wire and pull the coil straight up and out of the valve cover. For V6 models, mark the positions of the spark plug wires, detach them from the coil pack, disconnect the electrical connector, and remove the mounting bolts. Lift the coil pack from the cylinder head. Installation is the reverse of removal.