how to fix the P0301 misfire code in my Volkswagen Golf MK7 (2015-2019)?

Solution

1. Preparation

• Gather tools and materials: OBD-II scanner, socket set, torque wrench, multimeter, compression gauge, new spark plugs, new ignition coil (if needed), and fuel injector cleaner.
• Ensure the vehicle is parked on a level surface and the engine is cool.

2. Replace Spark Plug (if needed)

• Remove the engine cover (if applicable) using the socket set.
• Disconnect the ignition coil electrical connector.
• Remove the ignition coil from cylinder 1 using the socket set.
• Unscrew the spark plug using the spark plug socket.
• Inspect the old spark plug for wear or damage; replace it with a new one, ensuring it is gapped correctly (usually 0.028-0.031 inches).
• Reinstall the ignition coil and reconnect the electrical connector. Torque the ignition coil screws to the manufacturer’s specifications (usually around 7-9 ft-lbs).

3. Replace Ignition Coil (if needed)

• If the ignition coil appears damaged or faulty, replace it:
  • Follow the steps to remove the ignition coil as outlined above.
  • Install the new ignition coil and reconnect the electrical connector securely.
  • Reinstall any components removed during the process.

4. Clean or Replace Fuel Injector (if needed)

• If the fuel injector is suspected to be malfunctioning, clean it with a fuel injector cleaner or replace it:
  • Disconnect the fuel injector wiring harness and fuel line (be cautious of fuel spill).
  • Remove the old fuel injector from the rail using the socket set.
  • Install the new or cleaned fuel injector, ensuring it is seated properly.
  • Reconnect the fuel line and wiring harness securely.

5. Perform Compression Test

• Attach the compression gauge to the spark plug hole of cylinder 1.
• Crank the engine to take a reading. The compression should be within the manufacturer's specified range (typically around 150-200 psi).
• If compression is low, further investigation may be required (valve issues, head gasket failure).