how to handle a P0304 code on 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 necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug gap tool.
• Remove the ignition coil cover (if applicable) to access the spark plug.
• Using a spark plug socket, remove the spark plug from cylinder 4.
• Inspect the spark plug for wear; replace if it shows signs of wear or fouling.
• Ensure the new spark plug is gapped correctly according to manufacturer specifications.
• Install the new spark plug by hand, then torque it to the manufacturer's specifications (usually around 13-15 lb-ft).

3. Check and Replace Ignition Coil

• Tools Required: Socket set.
• Remove the ignition coil from cylinder 4 by unscrewing the bolts securing it.
• Inspect the coil for cracks or damage. If it appears faulty, replace it with a new coil.
• Reinstall the ignition coil, ensuring it is seated properly and secured with bolts.

4. Inspect and Clean Fuel Injector

• Tools Required: Fuel injector cleaning kit (if applicable), multimeter.
• Disconnect the electrical connector from the fuel injector on cylinder 4.
• Use a multimeter to measure the injector’s resistance to ensure it is within specifications.
• If necessary, remove the fuel injector and inspect for clogs. Clean or replace as needed.
• Reinstall the injector and reconnect the electrical connector.

5. Conduct Compression Test (if misfire persists)

• Tools Required: Compression tester.
• Remove the spark plug from cylinder 4 again.
• Insert the compression tester into the spark plug hole and crank the engine to measure compression.
• Compare the reading to the manufacturer's specifications for normal compression.
• If compression is low, further diagnostics may be needed to check for internal engine issues.