how to fix P0304 misfire code in Ford F-150 13th Generation (2015-2020)

Learn how to diagnose and fix P0304 cylinder 4 misfire in Ford F-150 (2015-2020). Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool down completely before starting any work.

2. Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket
• Remove the ignition coil from cylinder 4 by unscrewing the bolts and disconnecting the electrical connector.
• Use the spark plug socket to remove the old spark plug from cylinder 4.
• Inspect the spark plug for wear or damage; replace it if necessary.
• Install the new spark plug, tightening it to the manufacturer's specified torque (usually around 13 ft-lbs).
• Reinstall the ignition coil and reconnect the electrical connector.

3. Replace Ignition Coil

• If the spark plug is fine, proceed to replace the ignition coil.
• Tools Required: Socket set
• Remove the ignition coil for cylinder 4 as previously described.
• Install the new ignition coil, ensuring it is seated properly and securing it with the bolts.
• Reconnect the electrical connector.

4. Inspect and Replace Fuel Injector

• If misfires persist, inspect the fuel injector for cylinder 4.
• Tools Required: Fuel injector puller, socket set
• Remove the fuel rail if necessary to access the injector.
• Disconnect the fuel line and electrical connector from the injector.
• Remove the old fuel injector and replace it with a new one, ensuring proper sealing.
• Reassemble the fuel rail and reconnect all lines and connectors.

5. Conclusion

• Reconnect the negative battery terminal.
• Start the engine and observe for any misfire symptoms.