how to fix P0303 misfire code in 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 required tools and parts.
• Disconnect the negative battery cable to ensure safety.
• Allow the engine to cool down before starting any work.

2. Inspect and Replace Ignition Components

• Inspect Spark Plug:

  • Remove the spark plug from cylinder 3 using a spark plug socket.
  • Inspect for fouling, wear, or damage.
  • Replace with a new spark plug if necessary (use OEM specifications for gap size).

• Inspect Ignition Coil:

  • Disconnect the ignition coil connector.
  • Remove the ignition coil from cylinder 3.
  • Test the coil with a multimeter (refer to specifications for resistance values).
  • Replace if faulty.

3. Check Fuel Injector

• Fuel Injector Removal:

  • Relieve fuel system pressure by removing the fuel pump relay and starting the engine until it stalls.
  • Disconnect the fuel injector connector and remove the injector from cylinder 3.

• Testing the Injector:

  • Use a multimeter to check the injector resistance (should be within manufacturer specifications).
  • Replace the injector if it fails the test.

4. Compression Test

• Perform Compression Test:
  • Remove all spark plugs.
  • Insert the compression gauge into the spark plug hole of cylinder 3.
  • Crank the engine and note the compression reading.
  • Compare with specifications; replace the cylinder head gasket or repair the engine if compression is low.

5. Reassemble and Reconnect

• Reinstall all components in reverse order of removal.
• Reconnect the negative battery cable.
• Clear any codes using the OBD-II scanner.