how to fix P0303 code in Ford F-150 12th Generation (2009-2014)

Learn how to diagnose and fix P0303 cylinder 3 misfire in Ford F-150 (2009-2014). Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to avoid any electrical shorts.
• Allow the engine to cool down if it has been running.

2. 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 a spark plug socket.
• Inspect the new spark plug and ensure it is gapped correctly according to manufacturer specifications.
• Install the new spark plug and torque it to the manufacturer-recommended specification (generally around 13-15 lb-ft).
• Reinstall the ignition coil and reconnect the electrical connector.

3. Test Ignition Coil

• Tools Required: Multimeter.
• Unplug the ignition coil connector.
• Measure the resistance across the coil terminals; compare the readings against the service manual specifications.
• If the coil is out of specification, replace it with a new ignition coil.

4. Check Fuel Injector

• Tools Required: Fuel injector cleaner, basic hand tools.
• Remove the fuel injector from cylinder 3.
• Use a fuel injector cleaner to clean the injector.
• Reinstall the injector and ensure it is seated properly.

5. Perform Compression Test

• Tools Required: Compression gauge.
• Remove the spark plug from cylinder 3.
• Insert the compression gauge into the spark plug hole and crank the engine for a few seconds.
• Record the compression reading and compare it to the manufacturer's specifications (usually around 120-150 psi for most engines).
• If the compression is low, further engine diagnostics may be necessary.