why does my BMW 5 Series F10/F11 (2010-2017) have an unstable idle at stoplights

Solution

1. Preparation

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

2. Clean the Throttle Body

• Remove the air intake duct to access the throttle body.
• Use throttle body cleaner and a soft brush to clean the throttle plate and surrounding areas.
• Reassemble the intake duct and reconnect any sensors or hoses.

3. Address Vacuum Leaks

• Inspect all vacuum hoses for cracks or disconnections.
• Replace any damaged hoses with OEM parts.
• If applicable, replace the intake manifold gasket to prevent air leaks.

4. Inspect and Test the IAC Valve

• Locate the IAC valve, usually mounted on the throttle body or intake manifold.
• Disconnect the electrical connector and remove the valve.
• Clean the IAC valve with appropriate cleaner and ensure it moves freely.
• Reinstall the IAC valve and reconnect the electrical connector.

5. Replace Spark Plugs and Coils (if necessary)

• Remove the engine cover to access the ignition coils and spark plugs.
• Disconnect the ignition coil connectors and remove the coils.
• Remove the old spark plugs using a spark plug socket.
• Install new spark plugs, ensuring the correct gap is set, and torque them to manufacturer specifications.
• Reinstall the ignition coils.

6. Reconnect the Battery

• Reconnect the negative battery terminal.
• Start the engine and allow it to reach operating temperature.