how to fix P0303 misfire code on Ford F-150 12th Generation (2009-2014)

Learn how to diagnose and fix P0303 cylinder 3 misfire in Ford F-150. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather tools and parts necessary for the repair.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Replace Spark Plug and Ignition Coil

• Sub-steps:
  1. Remove the engine cover (if applicable) using a socket set.
  2. Disconnect the electrical connector from the ignition coil on cylinder 3.
  3. Remove the ignition coil by unbolting it and pulling it straight out.
  4. Remove the spark plug using a spark plug socket and ratchet.
  5. Inspect the spark plug for signs of wear or damage and replace it if necessary.
  6. Install the new spark plug and torque it to the manufacturer's specifications (typically around 13 lb-ft).
  7. Install the new ignition coil and reconnect the electrical connector.

3. Inspect and Clean Fuel Injector

• Sub-steps:
  1. Disconnect the fuel injector connector for cylinder 3.
  2. Remove the fuel rail (if necessary) to access the injector.
  3. Inspect the fuel injector for clogs or damage; clean using an appropriate injector cleaner if needed.
  4. Reinstall the fuel injector ensuring proper seating.
  5. Reattach the fuel rail and reconnect the fuel injector connector.

4. Check for Vacuum Leaks

• Sub-steps:
  1. Use a smoke machine or carburetor cleaner to check for vacuum leaks around the intake manifold and throttle body.
  2. If leaks are found, replace the affected gaskets or hoses.

5. Reconnect Battery and Clear Codes

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0303 code from the system.