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 tools and parts needed for repair.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool down if it has been running.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the ignition coil from cylinder 3 by unbolting it and disconnecting the electrical connector.
• Remove the spark plug using the spark plug socket. Inspect it for wear, carbon buildup, or damage.
• If necessary, replace the spark plug with a new one, ensuring it is gapped to manufacturer specifications (typically around 0.030-0.035 inches).
• Reinstall the ignition coil and reconnect the electrical connector.

3. Inspect and Replace Ignition Coil

• If the spark plug is in good condition, test the ignition coil for proper operation using a multimeter.
• If the ignition coil is faulty, remove the old coil and replace it with a new one.
• Ensure the new coil is seated properly and reconnect the electrical connector.

4. Inspect and Clean Fuel Injector

• If ignition components are in good condition, check the fuel injector for cylinder 3.
• Disconnect the fuel injector connector and remove the injector from the rail.
• Clean the injector using a fuel injector cleaning kit or replace it if necessary.
• Reinstall the injector and reconnect the electrical connector.

5. Reassemble and Test

• Reconnect the negative battery terminal.
• Start the engine and allow it to idle. Monitor for any misfire codes or symptoms.
• Conduct a road test to ensure the performance has returned to normal.