BMW 528i xDrive rough idle issue when cold in drive only on BMW 528i xDrive

Some BMW 528i xDrive owners report experiencing a rough idle issue specifically when the engine is cold and the transmission is in DRIVE, lasting for about 5 seconds before settling to normal. This problem does not occur in REVERSE gear. Potential causes identified include issues with the idle control valve (ICV) or the Vanos system, which may lead to oscillations in idle speed. Owners are also advised to check the functionality of the electrically activated valve, as signal or mechanical problems could contribute to the rough idle. Additionally, some owners note that checking for a slight vacuum when removing the oil filler cap while the car is idling can provide insights into the engine's condition. It is recommended that affected owners consult a mechanic specializing in BMW vehicles for a thorough inspection and proper diagnosis.