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 necessary tools and parts.
• Disconnect the negative battery terminal to avoid electrical shock.
• Allow the engine to cool if it has been running.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the engine cover if necessary.
• Remove the spark plug wire or ignition coil connector from cylinder 4.
• Use a spark plug socket to unscrew and remove the spark plug.
• Inspect the spark plug for wear or damage. Replace with a new spark plug if necessary (OEM recommended gap).
• Reinstall the spark plug and secure it to the specified torque (usually around 13-15 lb-ft).

3. Inspect and Replace Ignition Coil

• Tools Required: Socket set.
• Remove the ignition coil mounting bolts from cylinder 4.
• Disconnect the ignition coil connector.
• Remove the ignition coil from the spark plug.
• Inspect for cracks or damage and replace the ignition coil if necessary.
• Reinstall the ignition coil, reconnect the connector, and secure the bolts.

4. Check and Replace Fuel Injector

• Tools Required: Fuel injector removal tool, socket set.
• Relieve fuel system pressure by removing the fuel pump fuse and running the engine until it stalls.
• Disconnect the fuel lines from the fuel injector on cylinder 4, using a fuel line tool if necessary.
• Remove the retaining clips and pull out the fuel injector.
• Inspect the injector for clogs or damage and replace if necessary.
• Install the new fuel injector, reconnect fuel lines, and replace the retaining clips.

5. Final Assembly and Battery Reconnection

• Reconnect any components that were removed (engine cover, connectors).
• Reconnect the negative battery terminal.
• Start the engine and check for any warning lights.