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

Learn how to diagnose and fix P0304 cylinder 4 misfire in Ford F-150 12th Generation. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather tools and parts required.
• Disconnect the negative battery terminal to ensure safety while working on the electrical components.

2. Replace Spark Plug

• Remove the ignition coil for cylinder 4:
  1. Unplug the electrical connector from the ignition coil.
  2. Remove the bolts securing the coil using a socket set.
  3. Gently pull the coil out of the spark plug well.
• Remove the spark plug:
  1. Use a spark plug socket to unscrew the spark plug from the cylinder head.
  2. Inspect the old spark plug for wear or oil fouling.
• Install the new spark plug:
  1. Apply a small amount of anti-seize compound on the threads of the new plug.
  2. Hand-tighten the new spark plug into the cylinder head, then torque to 13 lb-ft using a torque wrench.

3. Check and Replace Ignition Coil

• If the ignition coil was found to be faulty:
  1. Install the new ignition coil by reversing the removal steps.
  2. Ensure the electrical connector snaps in securely.

4. Inspect and Replace Fuel Injector (if necessary)

• If the fuel injector is faulty:
  1. Disconnect the electrical connector from the fuel injector.
  2. Remove any retaining clips and pull the injector out of the intake manifold.
  3. Replace with a new fuel injector, ensuring it seats properly.
  4. Reconnect the electrical connector.

5. Reassemble and Reconnect Battery

• Reinstall any components removed for access.
• Reconnect the negative battery terminal.