how to fix the misfire on my BMW 3 Series F30/F31 (2012-2019) with P0302 code?

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface, and the engine is cool.
• Disconnect the negative battery terminal to ensure safety while working.

2. Replace Ignition Coil

• Tools Required: Socket set, torque wrench.
• Sub-steps:
  1. Remove the engine cover if applicable.
  2. Disconnect the electrical connector from the ignition coil on cylinder 2.
  3. Remove the retaining bolt(s) of the ignition coil and pull the ignition coil out.
  4. Install the new ignition coil by reversing the removal steps and torque the bolt to 10 Nm (7 lb-ft).

3. Replace Spark Plug

• Tools Required: Spark plug socket, torque wrench, gap gauge.
• Sub-steps:
  1. Remove the ignition coil from cylinder 2 again to access the spark plug.
  2. Use a spark plug socket to unscrew and remove the old spark plug.
  3. Check the gap on the new spark plug and adjust it to the manufacturer’s specification (typically 0.8-1.0 mm or 0.031-0.039 inches).
  4. Install the new spark plug and torque it to 25 Nm (18 lb-ft).
  5. Reinstall the ignition coil.

4. Test Fuel Injector

• Tools Required: Fuel injector cleaning kit or multimeter (if testing resistance).
• Sub-steps:
  1. Disconnect the fuel injector connector for cylinder 2.
  2. Check the resistance of the injector with a multimeter; it should be within the manufacturer's specifications (typically around 12-16 ohms).
  3. If faulty, replace the fuel injector with a new one.
  4. Reconnect the fuel injector connector.

5. Clear Codes and Test Drive

• Use the OBD-II scanner to clear the diagnostic trouble codes.
• Reconnect the battery terminal and start the engine.
• Perform a test drive to ensure the misfire has been resolved.