how to diagnose P0301 misfire in my Volkswagen Golf MK7.5 (2020-Present)?

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, fuel pressure gauge, compression tester.
• Safety Warnings: Disconnect the battery before working on electrical systems; allow the engine to cool before performing any tests.

2. Replace Ignition Components

• Sub-steps:
  1. Remove the engine cover (if applicable) using a socket set.
  2. Disconnect the electrical connector from the ignition coil in cylinder 1.
  3. Unbolt the ignition coil from the cylinder head.
  4. Remove the spark plug from cylinder 1 using a spark plug socket.
  5. Inspect the old spark plug for wear—replace if necessary.
  6. Install a new spark plug and torque it to the manufacturer's specification (typically around 22 lb-ft).
  7. Install the new ignition coil and secure it with bolts.
  8. Reconnect the electrical connector to the ignition coil.

3. Check Fuel Delivery

• Sub-steps:
  1. Connect the fuel pressure gauge to the fuel rail’s Schrader valve.
  2. Turn the ignition to the ON position (do not start the engine) to check the fuel pressure.
  3. Compare the pressure reading to the manufacturer's specifications (typically around 58-65 psi).
  4. If pressure is low, investigate the fuel pump, filter, and injectors.

4. Conduct Compression Test

• Sub-steps:
  1. Remove the ignition coil and spark plug from cylinder 1.
  2. Install the compression tester into the spark plug hole.
  3. Crank the engine for a few seconds and record the compression reading.
  4. Compare the result to the manufacturer's specifications (typically around 150-200 psi).
  5. If compression is low, further diagnosis may be needed for potential engine mechanical issues.