E60 525i Engine Vibration

[Kooly]

Hi, need some advises and recommendation. Just got an E60 525i for 3 mths, mileage about 120000km when i got it. Had drove about 7k myself. Ride was cool and nice. Initially the idling speed was at about 600rpm(visual from speedometer).

Observation:
- about 3 weeks ago, idling speed will increased to about 800rpm
-last week, every first start of the day and prolong stop(more than 6 hours),engine will vibrate and rpm varies from 600-900rpm. Will need to stop the engine and restart, everything back to normal.
-power lost observed during moved off with the engine vibration. After stop and restart, seems normal again.

What could possibly goes wrong or about to fail? Was suspecting either the fuel system, air delivery to the engine or anything to do with combustion(ie injectors, ignition coil, etc) that caused the vibration.

If any members did have some similar experiences, do give me some advices before i send the car for a check.

Thanks in advance.

 

[hamburger]

Need not guess so much. Plug in the obd II and the answer is there.

 

[Citizen69]

Previously I had similar experiences only when at traffic lights stops. Gear is at D and pressing the foot brake with air con on. Sudden acceleration from stop also will vibrate violently before the gear engaged, making it a nightmare at traffic light turning or overtaking situations. Turns out that the solenoids that controls the 1st gear(and others) was supposedly worn. Changed the whole set of solenoids, new ATF, and no more vibration. Not too sure whether is the same cause.