how to fix P0300 misfire code on BMW 3 Series F30/F31 (2012-2019)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool down before starting work.

2. Spark Plug Replacement

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the engine cover if applicable.
• Disconnect the ignition coil connectors.
• Unscrew the ignition coils and remove them carefully.
• Use the spark plug socket to remove the old spark plugs.
• Inspect the spark plug gap and replace with new spark plugs if necessary.
• Install the new spark plugs to the manufacturer's specified torque (generally around 18-22 lb-ft).
• Reinstall the ignition coils and reconnect the connectors.

3. Ignition Coil Check/Replacement

• If the ignition coils are suspected to be faulty, replace them.
• Tools Required: Socket set, torque wrench.
• Remove the faulty ignition coils as described in the previous step.
• Install new ignition coils and torque to the manufacturer's specifications.

4. Fuel Injector Inspection/Replacement

• Tools Required: Fuel pressure gauge, injector puller (if needed).
• Connect a fuel pressure gauge to the fuel rail to check pressure; replace the fuel filter if pressure is low.
• If injectors are clogged, use an injector cleaner or replace them if necessary.
• Reinstall the fuel rail and ensure all connections are secure.

5. Vacuum Leak Inspection

• Inspect all vacuum lines for cracks or disconnections.
• Use a smoke tester if available to detect leaks.
• Replace any damaged hoses and ensure all connections are tight.

6. MAF Sensor Cleaning/Replacement

• Tools Required: MAF cleaner.
• Disconnect the MAF sensor connector and remove the sensor from the air intake.
• Clean the sensor with MAF cleaner and allow it to dry.
• Reinstall the sensor and reconnect the electrical connector.