how to fix P0303 code on Ford F-150 13th Generation (2015-2020)

Learn how to diagnose and fix P0303 cylinder 3 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 battery to ensure safety while working on electrical components.

2. Inspect and Replace Spark Plug

• Sub-steps:
  1. Remove the engine cover if applicable.
  2. Locate and remove the spark plug for cylinder 3 using a socket wrench (typically 5/8" socket).
  3. Inspect the spark plug for signs of fouling or wear (replace if necessary).
  4. Gap the new spark plug to manufacturer specifications (typically around 0.044 inches for Ford F-150).
  5. Install the new spark plug and torque to 13 lb-ft.

3. Check and Replace Ignition Coil

• Sub-steps:
  1. Remove the ignition coil connector from cylinder 3.
  2. Remove the ignition coil bolt and pull the coil out.
  3. Inspect the coil for damage or corrosion.
  4. Replace with a new ignition coil if faulty.
  5. Reinstall the ignition coil and reconnect the electrical connector.

4. Fuel Injector Inspection

• Sub-steps:
  1. Disconnect the fuel injector connector for cylinder 3.
  2. Remove the fuel rail if necessary to access the injector.
  3. Check the injector for proper operation using a multimeter.
  4. Replace the fuel injector if it is malfunctioning.
  5. Reinstall the fuel rail and reconnect the fuel injector connector.

5. Conduct Compression Test

• Sub-steps:
  1. Remove the spark plug for cylinder 3 again.
  2. Insert a compression gauge into the spark plug hole.
  3. Crank the engine and record the compression reading.
  4. Compare the reading to manufacturer specifications (typically around 120-150 psi).
  5. If the compression is low, investigate possible causes (valve issues, head gasket failure).