how can I fix the misfire issue with code P0301 on my BMW 3 Series G20/G21 (2019-2024)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the battery to avoid any electrical shorts.
• Allow the engine to cool before starting work.

2. Replace Spark Plug and Ignition Coil

• Tools Required: Spark plug socket, ratchet, torque wrench, pliers.
• Remove the engine cover if applicable.
• Disconnect the ignition coil connector from the ignition coil on cylinder 1.
• Remove the bolt securing the ignition coil and gently pull the coil out.
• Using the spark plug socket, remove the spark plug from cylinder 1.
• Install the new spark plug by hand to avoid cross-threading, then torque to the manufacturer’s specification (usually around 20 Nm).
• Insert the new ignition coil into place and secure it with the bolt. Reconnect the ignition coil connector.

3. Inspect and Clean Fuel Injector (if needed)

• Tools Required: Fuel injector cleaner, cleaning kit (optional), safety goggles.
• Detach the fuel injector connector for cylinder 1.
• Remove the fuel rail if necessary to access the injector.
• Clean the injector using a fuel injector cleaner or replace it if it is faulty.
• Reinstall the fuel rail and connectors securely.

4. Compression Test (if needed)

• Tools Required: Compression tester.
• Remove the spark plug from cylinder 1.
• Insert the compression tester into the spark plug hole and crank the engine for a few revolutions.
• Record the compression reading and compare it to the manufacturer’s specifications (typically 130-200 psi).
• If the compression is low, further investigation into the engine internals may be required.