how to troubleshoot P0301 misfire code in my BMW 3 Series G20/G21 (2019-2024)?

Solution

1. Spark Plug Replacement

1. Gather Tools and Parts:
   • Tools: Socket set, torque wrench, spark plug socket
   • Parts: New spark plug for cylinder 1
2. Remove Engine Cover:
   • Unscrew and remove any fasteners securing the engine cover.
3. Remove Spark Plug:
   • Disconnect the ignition coil connector and remove the ignition coil.
   • Use a spark plug socket to unscrew and remove the old spark plug.
4. Install New Spark Plug:
   • Apply anti-seize compound to the threads of the new spark plug.
   • Hand-tighten the spark plug, then use a torque wrench to tighten it to the manufacturer-recommended torque (usually around 18 lb-ft).
5. Reinstall Ignition Coil and Engine Cover:
   • Reinstall the ignition coil and secure the connector.
   • Replace the engine cover and secure it with the fasteners.

2. Ignition Coil Replacement (if necessary)

1. Gather Tools and Parts:
   • Tools: Socket set, torque wrench
   • Parts: New ignition coil
2. Remove Engine Cover (if not already done):
   • Follow the same steps as above to access the ignition coil.
3. Remove Old Ignition Coil:
   • Disconnect the electrical connector and unscrew the mounting bolts.
   • Carefully lift the old ignition coil out of the socket.
4. Install New Ignition Coil:
   • Position the new ignition coil in place and secure it with the bolts.
   • Reconnect the electrical connector.
5. Reinstall Engine Cover:
   • Replace and secure the engine cover.

3. Fuel Injector Inspection/Replacement (if necessary)

1. Gather Tools and Parts:
   • Tools: Socket set, fuel injector puller (if needed)
   • Parts: New fuel injector (if replacement is required)
2. Relieve Fuel Pressure:
   • Locate the fuel pump fuse and remove it, then start the engine to relieve pressure.
3. Remove Fuel Rail:
   • Disconnect fuel lines and electrical connectors from the fuel injectors.
   • Unbolt and remove the fuel rail from the engine.
4. Inspect or Replace Fuel Injector:
   • Remove the old fuel injector using a fuel injector puller if needed.
   • Install the new fuel injector, ensuring proper alignment and sealing.
5. Reassemble Components:
   • Reinstall the fuel rail and reconnect all lines and connectors.
   • Reinsert the fuel pump fuse and start the engine to check for proper operation.