how to fix P0303 misfire code on my 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 negative battery terminal to prevent electrical short circuits.
• Allow the engine to cool down before beginning work.

2. Inspect and Replace Ignition Coil (if necessary)

• Tools Required: Socket set, torque wrench.
• Sub-steps:
  1. Remove the engine cover if applicable.
  2. Disconnect the wiring harness from the ignition coil on cylinder 3.
  3. Remove the bolts securing the ignition coil using a socket.
  4. Pull the ignition coil out of the spark plug well.
  5. Install the new ignition coil and secure it with bolts, torquing to manufacturer specifications (usually around 10-15 lb-ft).
  6. Reconnect the wiring harness.

3. Inspect and Replace Spark Plug (if necessary)

• Tools Required: Spark plug socket, gap gauge, torque wrench.
• Sub-steps:
  1. Remove the ignition coil from cylinder 3 (refer to the previous step).
  2. Use a spark plug socket to remove the spark plug by turning counterclockwise.
  3. Inspect the spark plug for signs of wear or fouling. Check the gap using a gap gauge and adjust if necessary (typically around 0.050 inches).
  4. Install a new spark plug, hand-tightening it, then torque to the manufacturer’s specification (usually around 12-15 lb-ft).
  5. Reinstall the ignition coil.

4. Inspect and Clean Fuel Injector (if necessary)

• Tools Required: Fuel injector cleaner, multimeter (for electrical testing).
• Sub-steps:
  1. Disconnect the fuel line and electrical connector from the fuel injector on cylinder 3.
  2. Remove the fuel injector using the appropriate tools.
  3. Clean the injector using a fuel injector cleaner or replace it if it is clogged.
  4. Test the injector with a multimeter for proper resistance (typically 12-16 ohms).
  5. Reinstall the cleaned or new fuel injector ensuring proper sealing.

5. Perform a Compression Test (if necessary)

• Tools Required: Compression tester.
• Sub-steps:
  1. Remove the spark plug from cylinder 3.
  2. Insert the compression tester into the spark plug hole.
  3. Crank the engine for several seconds and record the compression reading.
  4. Compare the reading to the manufacturer’s specifications (usually around 120-150 psi).
  5. If compression is low, further investigation into internal engine issues is required.