how to resolve the P0303 misfire code on my Ford F-150 Fourteenth Generation (2021-present)

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 necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Spark Plug

• Tools Required: Spark plug socket, ratchet, torque wrench.
• Remove the ignition coil from cylinder 3:
  1. Disconnect the electrical connector from the ignition coil.
  2. Remove the mounting bolts using a socket.
  3. Carefully pull the ignition coil out.
• Remove the spark plug using the spark plug socket:
  1. Turn counterclockwise to remove.
  2. Inspect the spark plug for wear, carbon buildup, or damage.
• If worn, replace with a new spark plug (specify OEM part). Torque to manufacturer specifications (typically around 13-15 lb-ft).

3. Inspect and Replace Ignition Coil

• Tools Required: Socket set, torque wrench.
• If the ignition coil shows signs of damage:
  1. Install the new ignition coil by reversing the removal steps.
  2. Torque the mounting bolts to manufacturer specifications.
  3. Reconnect the electrical connector.

4. Inspect and Replace Fuel Injector

• Tools Required: Fuel injector removal tool, O-rings.
• If the fuel injector is faulty:
  1. Relieve fuel system pressure using the service manual procedure.
  2. Disconnect the fuel line and electrical connector from the injector.
  3. Remove the injector from the fuel rail.
  4. Install the new injector with new O-rings.
  5. Reconnect the fuel line and electrical connector.

5. Perform a Compression Test

• Tools Required: Compression tester.
• If compression is low:
  1. Remove the spark plug from cylinder 3.
  2. Insert the compression tester into the spark plug hole.
  3. Crank the engine to obtain a reading.
  4. If compression is low, further investigation (e.g., valve issues, head gasket) is necessary.