my BMW 5 Series G30/G31 (2017-2024) has a persistent misfire, what could be wrong?

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the battery to prevent electrical shorts.

2. Replace Spark Plugs

• Remove the engine cover if applicable.
• Use a socket set to remove the ignition coils.
• Extract the old spark plugs with a spark plug socket.
• Inspect the old spark plugs for signs of wear (e.g., carbon buildup).
• Install new spark plugs with the correct gap (consult manufacturer specifications).

3. Inspect and Replace Ignition Coils (if necessary)

• If any ignition coils were tested and found faulty, remove them using the socket set.
• Replace with new ignition coils ensuring they are securely seated.
• Reconnect electrical connectors to the ignition coils.

4. Check and Replace Fuel Injectors (if necessary)

• Remove the fuel rail (if injectors are faulty) after relieving fuel pressure.
• Replace any malfunctioning fuel injectors with new units.
• Reassemble fuel rail and ensure all connections are tight.

5. Inspect and Repair Vacuum Leaks

• Visually inspect vacuum hoses for cracks or disconnections.
• Replace any damaged hoses and ensure all connections are secure.
• Perform a smoke test if necessary to find hard-to-detect leaks.

Tools Required:

• OBD-II scanner
• Socket set
• Torque wrench
• Multimeter
• Spark plug socket
• Fuel injector tester (optional)

Parts Required:

• Spark plugs
• Ignition coils (if faulty)
• Fuel injectors (if faulty)
• Vacuum hoses (if damaged)

Estimated Repair Time: 2-4 hours

Safety Warnings:

• Disconnect battery before working on electrical systems.
• Allow engine to cool before opening any components.