4wheelsMD

I got a 530XI (6/2006). I started having problem when I tried to get the car off my garage that is a bit uphill. The care in D trembled and I was terrified. I took her to the repare shop but they couln;t find anything. Soon the car started to loose power (severe arhythmia) in low rpm when I tried to accelerate. Again the diagnostics failed to find anything. I had to drive to convince the mechanic and now my car is 5 days in the repair shop. They told me that there was a mechanical problem with valvetronic, they changed it and the same problem persists. They have also changed the spark plugs (at 50.000K m) but nothing. I am in despare. Has anyone any idea what is happening?