how to fix the P0303 misfire code on my Ford F-150

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

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket
• Remove the ignition coil from cylinder 3:
  1. Unscrew the retaining bolts and disconnect the electrical connector.
  2. Carefully pull the ignition coil out.
• Remove the spark plug using a spark plug socket:
  1. Turn counterclockwise to unscrew the old spark plug.
  2. Inspect the spark plug for wear; replace if necessary.
• Install a new spark plug:
  1. Hand-tighten the new spark plug, then use a torque wrench to tighten to the manufacturer’s specification (usually around 13-15 lb-ft).

3. Inspect and Replace Ignition Coil

• Tools Required: Socket set
• If the ignition coil is faulty:
  1. Install a new ignition coil by aligning it over the spark plug and pushing it down until it clicks into place.
  2. Reconnect the electrical connector and secure with the retaining bolts.

4. Clean or Replace Fuel Injector

• Tools Required: Fuel injector cleaning kit or replacement injector
• If the fuel injector is clogged:
  1. Disconnect the fuel line and electrical connector from the injector.
  2. Remove the injector from the rail.
  3. Clean the injector using a cleaning kit or replace it with a new one.
  4. Reinstall the injector, reconnect the fuel line, and electrical connector.

5. Final Assembly

• Reinstall any components that were removed during the process.
• Reconnect the negative battery terminal.