how to fix P0304 misfire code in Volkswagen Golf MK5 (2004-2008)?

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the engine is cool and disconnect the battery to avoid electrical issues.

2. Inspect and Replace Spark Plug

• Tools Required: Spark plug socket, torque wrench.
• Remove the ignition coil for cylinder 4.
  • Unplug the electrical connector.
  • Unbolt the coil and pull it out.
• Remove the spark plug using the spark plug socket.
• Inspect the spark plug for signs of wear or fouling; replace if necessary.
• Install a new spark plug, torquing to the manufacturer's specifications (typically around 22 lb-ft).

3. Inspect and Replace Ignition Coil

• Check the ignition coil for cylinder 4 for any visible damage.
• If faulty, install a new ignition coil:
  • Place the new coil into the spark plug well.
  • Reconnect the electrical connector.
  • Secure the coil with the mounting bolt.

4. Check and Clean Fuel Injector

• Remove the fuel injector for cylinder 4:
  • Disconnect the fuel injector connector.
  • Remove the fuel rail if necessary to access the injector.
• Inspect the injector for clogs and clean it using a fuel injector cleaner or replace it if defective.
• Reinstall the injector into the rail (if removed) and reconnect the electrical connector.

5. Reassemble and Reconnect Battery

• Reinstall any components that were removed during the inspection process.
• Reconnect the battery terminals securely.