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

Learn how to diagnose and fix P0303 cylinder 3 misfire in Ford F-150 12th Generation. 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.
• Allow the engine to cool if it has been running.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, spark plug socket, torque wrench
• Remove the ignition coil from cylinder 3:
  1. Disconnect the electrical connector from the ignition coil.
  2. Remove bolts securing the ignition coil and pull it out.
• Remove the spark plug:
  1. Use the spark plug socket to unscrew the spark plug from cylinder 3.
  2. Inspect the spark plug for signs of wear (e.g., oil or carbon fouling).
• Install a new spark plug:
  1. Apply anti-seize compound on the threads of the new spark plug.
  2. Torque the spark plug to manufacturer specifications (typically around 13-15 lb-ft).
• Reinstall the ignition coil onto the spark plug.

3. Check and Replace Ignition Coil

• If the spark plug is fine, inspect the ignition coil:
  1. Use a multimeter to check for proper resistance in the ignition coil.
  2. If faulty, replace the ignition coil with a new one for cylinder 3.
• Reconnect the electrical connector.

4. Fuel Injector Inspection

• If misfire persists, check the fuel injector:
  1. Disconnect the fuel injector connector for cylinder 3.
  2. Use a noid light to check for signal at the connector; if none, check wiring.
  3. If the injector is not functioning, replace it with a new one.

5. Verify Compression

• If issues remain, perform a compression test:
  1. Remove the spark plug from cylinder 3 and connect the compression tester.
  2. Crank the engine and read the compression value; it should be within manufacturer specifications.
  3. If low, further diagnosis is needed for potential internal engine issues.