how to fix P0304 misfire code in Ford F-150 14th Generation (2021-2024)

Learn how to diagnose and fix P0304 cylinder 4 misfire in Ford F-150 (2021-2024). Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather tools and parts required.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shock.

2. Inspect and Replace Spark Plug

• Tools Required: Spark plug socket, ratchet, torque wrench
• Remove the ignition coil from cylinder 4 by taking out the bolts and disconnecting the electrical connector.
• Remove the spark plug from cylinder 4 using a spark plug socket.
• Inspect the spark plug for wear; replace with a new one if it shows signs of damage or excessive wear.
• Install the new spark plug, tightening it to the manufacturer's specified torque (typically around 13-15 lb-ft).
• Reattach the ignition coil, ensuring the electrical connector is secure.

3. Inspect and Replace Ignition Coil

• Tools Required: Socket set, torque wrench
• If the spark plug is in good condition, inspect the ignition coil for signs of wear or failure.
• Remove the ignition coil from cylinder 4 and replace it with a new one if necessary.
• Ensure the new ignition coil is properly seated and the electrical connector is reattached securely.

4. Test Fuel Injector

• Tools Required: Fuel injector cleaner, multimeter
• Check the fuel injector's electrical connection using a multimeter to ensure it is functioning correctly.
• If the fuel injector is faulty, replace it with a new one.
• Clean the fuel injector using a fuel injector cleaning kit if it is clogged.

5. Compression Test

• Tools Required: Compression tester
• Perform a compression test on cylinder 4 to ensure it has adequate compression (typically around 120 psi or higher).
• If compression is low, further inspection of the cylinder head, valves, and piston rings may be required.