Verify that the engine is in good mechanical condition before continuing with this diagnostic.
- Turn ON the ignition.
- Inspect the fuse that supplies voltage to the ignition coils. If the fuse is open, test the spliced circuits and the individual ignition coils for a short to ground.
- Disconnect the affected ignition coil.
- Connect a test lamp between the ignition voltage circuit and a good ground.
- With the test lamp still connected, measure for battery voltage between the ignition voltage circuit and a good ground.
- If the voltage is not within 0.5 volt of battery voltage, repair the high resistance or the open in the ignition voltage circuit.
- Turn OFF the ignition, and all electrical accessories. Allow sufficient time for all of the control modules to power down before taking a resistance measurement.
- Measure for a proper value of less than 5 ohms of resistance between the ground circuit of the affected ignition coil and a good ground.
- If the resistance is more than 5 ohms, repair the high resistance or the open in the ground circuit.
- Exchange the affected ignition coil with the ignition coil of a good cylinder.
Start the engine and observe the scan tool.
If the misfire transfers with the suspect ignition coil, replace as needed