how to fix P0304 code on Ford F-150 12th Generation (2009-2014)

Learn how to diagnose and fix P0304 cylinder 4 misfire in Ford F-150 (2009-2014). Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool completely before starting work.

2. Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug gap tool.
• Remove the ignition coil from cylinder 4 by unbolting it and disconnecting the electrical connector.
• Use a spark plug socket to remove the old spark plug.
• Check the gap of the new spark plug using the gap tool and adjust to manufacturer's specifications.
• Install the new spark plug and torque it to the specified value (typically around 13 lb-ft).
• Reinstall the ignition coil.

3. Inspect and Replace Ignition Coil (if necessary)

• If the ignition coil for cylinder 4 appears damaged, remove it as described above.
• Replace it with a new ignition coil.
• Ensure all connections are secure and reconnect the electrical connector.

4. Check and Replace Fuel Injector (if necessary)

• Disconnect the fuel supply line and electrical connector from the fuel injector for cylinder 4.
• Remove the old fuel injector.
• Install the new fuel injector and reconnect the fuel line and electrical connector.

5. Reconnect Battery and Clear Codes

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0304 code from the ECU.