how to fix the P0301 misfire code in my BMW 3 Series F30/F31 (2012-2019)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical issues.
• Allow the engine to cool down before beginning.

2. Replace Spark Plug and Ignition Coil

• Tools Required: Socket set, torque wrench, dielectric grease.
• Sub-steps:
  1. Remove the engine cover (if applicable) by unscrewing any fasteners.
  2. Disconnect the ignition coil connector for cylinder 1.
  3. Remove the ignition coil by unscrewing it from its mount.
  4. Remove the spark plug using a spark plug socket.
  5. Inspect the old spark plug for wear; replace if necessary with the correct OEM part.
  6. Install the new spark plug to the recommended torque specification (typically around 20 Nm).
  7. Apply dielectric grease to the ignition coil connector.
  8. Reinstall the ignition coil and reconnect the electrical connector.

3. Replace Fuel Injector (if necessary)

• Tools Required: Fuel injector removal tool, O-ring lubricant.
• Sub-steps:
  1. Relieve the fuel system pressure by removing the fuel pump fuse and starting the engine until it stalls.
  2. Disconnect the fuel lines from the injector rail (use caution, as fuel may spray).
  3. Remove the injector harness connectors.
  4. Remove the fuel rail to access the injector.
  5. Remove the old injector and install the new one with lubricated O-rings.
  6. Reattach the fuel rail and reconnect all electrical connectors.

4. Reassemble and Test

• Reattach any components removed during the process (engine cover, etc.).
• Reconnect the negative battery terminal.
• Start the engine and check for any unusual sounds or warning lights.