how to handle a misfire in my Volkswagen Golf MK7 (2015-2019) with P0303 code

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the battery to ensure safety while working on electrical components.
• Allow the engine to cool down before beginning work.

2. Replace Spark Plug

• Tools Required: Spark plug socket, ratchet, torque wrench.
• Remove the ignition coil from cylinder 3:
  1. Disconnect the electrical connector from the ignition coil.
  2. Remove the bolt securing the ignition coil and gently pull it out.
• Remove the spark plug:
  1. Use the spark plug socket to remove the spark plug from cylinder 3.
• Install a new spark plug:
  1. Apply anti-seize compound on the threads of the new spark plug.
  2. Hand-tighten the spark plug into the cylinder head, then use a torque wrench to tighten to manufacturer specifications (typically around 22 ft-lbs).
• Reinstall the ignition coil:
  1. Place the ignition coil over the new spark plug and secure it with the bolt.
  2. Reconnect the electrical connector.

3. Replace Ignition Coil (if necessary)

• If the ignition coil tested faulty, procure a new ignition coil.
• Follow the same steps as above for removing and replacing the ignition coil.

4. Inspect and Test Fuel Injector

• Tools Required: Fuel injector cleaning kit or multimeter.
• Remove the fuel rail to access the injector:
  1. Relieve fuel pressure by removing the fuel pump fuse and running the engine until it stalls.
  2. Disconnect fuel lines and electrical connectors from the fuel injector.
  3. Remove the fuel injector from the rail.
• Test the injector:
  1. Use a multimeter to check the injector resistance; compare with specifications.
  2. Clean or replace the injector as needed.
• Reinstall the fuel injector, fuel rail, and reconnect all lines and electrical connectors.

5. Clear Codes and Test Drive

• Reconnect the battery and use the OBD-II scanner to clear the P0303 code.
• Test drive the vehicle to ensure the misfire has been resolved.