why does my BMW X5 F15 (2014-2019) have a rough idle when cold

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is on a level surface and the engine is cool.
• Disconnect the battery to prevent electrical issues while working on the vehicle.

2. Inspect and Replace Spark Plugs

• Remove ignition coils using a socket set.
• Extract spark plugs and inspect for wear or carbon buildup.
• Replace with OEM or equivalent spark plugs, ensuring proper torque (typically 18 lb-ft).
• Reinstall ignition coils securely.

3. Check and Replace Fuel Filter

• Locate the fuel filter; typically found along the fuel line.
• Relieve fuel pressure using the service port on the fuel rail.
• Disconnect fuel lines, noting orientation.
• Replace with a new filter, ensuring proper fittings and orientation.
• Reconnect the fuel lines and check for leaks.

4. Clean or Replace Mass Air Flow Sensor (MAF)

• Locate the MAF sensor in the air intake system.
• Disconnect the wiring harness and remove the sensor.
• Clean the sensor using MAF cleaner spray (do not use other cleaners).
• If cleaning does not resolve the issue, replace the MAF sensor with a new one.

5. Verify Engine Coolant Temperature Sensor

• Locate the coolant temperature sensor.
• Disconnect the sensor and measure resistance using a multimeter to check specifications.
• Replace the sensor if it is out of range.