EratticIdle 
2006 BMW 5 Series Sedan 530i 4dr Sedan (3.0L 6cyl 6M)
Inconsistent Idle
 15 year BMW owner. This car/engine has an idle issue. If you are thinking of buying one observe how it idles after reaching temperature. As you stop, the car idle drops to normal. 2 seconds later it drops, shakes the car, returns to normal. Happens a lot. Been to dealer 6 times. Have driven other 2006 and 2007 530s and noted the SAME issue although some vehicles not quite as noticeable. Worried about long term viability of this car.