why does my BMW 5 Series F10/F11 (2010-2017) have a rough idle after warm-up

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the negative battery terminal to ensure safety.
• Allow the engine to cool down before starting work.

2. Inspect and Replace Spark Plugs

• Remove the engine cover (if applicable).
• Use a socket set to remove the spark plug wires or ignition coils, taking care not to damage them.
• Remove each spark plug using a spark plug socket and inspect for wear (look for carbon buildup or excessive gap).
• Replace any faulty or worn spark plugs with new ones, ensuring they are gapped to manufacturer specifications (usually around 0.032-0.036 inches).
• Reinstall ignition coils or spark plug wires and the engine cover.

3. Check and Replace Ignition Coils (if necessary)

• If the ignition coils were identified as faulty in the diagnostics, proceed to replace them.
• Remove the bolts securing the ignition coils using a socket set.
• Carefully pull out the old ignition coils and replace them with new ones, ensuring a secure fit.
• Reconnect the wiring harness to each ignition coil.

4. Clean Throttle Body

• Remove the air intake duct connected to the throttle body using a screwdriver or socket set.
• Use throttle body cleaner and a soft brush to clean the throttle body, removing any carbon deposits.
• Ensure the throttle plate moves freely and is not obstructed.
• Reinstall the air intake duct securely.

5. Test and Reassemble

• Reconnect the negative battery terminal.
• Start the engine and allow it to reach operating temperature.
• Observe idle quality and check for any error codes using the OBD-II scanner.