how to fix P0300 misfire code in Ford F-150 Fourteenth Generation (2021-present)

Learn how to diagnose and fix P0300 random/multiple cylinder misfire in Ford F-150. 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 shock.
• Allow the engine to cool down before starting work.

2. Inspect and Replace Spark Plugs

• Tools Required: Socket set, spark plug socket, torque wrench.
• Remove the ignition coils by unscrewing the retaining bolts and disconnecting the electrical connectors.
• Use the spark plug socket to remove the spark plugs. Inspect them for wear or carbon deposits.
• Replace spark plugs with OEM or equivalent parts, ensuring they meet the manufacturer’s specifications.
• Torque the new spark plugs to the manufacturer’s specification (typically around 13-20 lb-ft).
• Reinstall the ignition coils in reverse order, ensuring all connections are secure.

3. Inspect and Replace Ignition Coils (if necessary)

• If spark plugs are in good condition, test the ignition coils using a multimeter.
• If any ignition coil is found faulty, remove the retaining bolts and disconnect the electrical connector.
• Replace with a new ignition coil, ensuring a tight fit and secure connection.
• Repeat for any other affected cylinders as indicated by the diagnostic steps.

4. Fuel System Inspection and Repair

• Tools Required: Fuel pressure gauge, appropriate hand tools.
• Attach the fuel pressure gauge to the fuel rail Schrader valve.
• Turn the ignition to the "ON" position (do not start) to check for proper fuel pressure as per manufacturer's specifications.
• If fuel pressure is low, inspect the fuel pump and fuel filter for blockage or failure. Replace as needed.

5. Vacuum Leak Check

• Visually inspect all vacuum lines for cracks or disconnections.
• If leaks are detected, replace the damaged hoses or reconnect them securely.
• Use a smoke machine if available to find hard-to-detect leaks.