Engine stalling

I have a problem with my 2003 325xi. If anybody have any ideas I would appreciate. The engine is unpredictably stalling when the clutch is slowly engaged at idle rpm in 1st and 2nd gears. It takes a lot of effort to prevent stalling when getting the car move from a stopped position, such as engaging clutch very slowly, giving more gas - which causes the cltuch almost slip if you give too much. This is an intermittent problem and when it comes it stays on weeks at a time, and unpredictably disappears at other times. When in the "stalling" state, it seems that the car also has a drop in torque, but not hp at high rpms. During the past 3 months it has been stalling most of the time. Dealer looked at it and changed the VANOS, after which for 3 weeks the car was running beautifully. Then it gradually deteriorated, now its pretty bad. I have driven stick shift cars for all my life, since age 12, and never had such a hard time handling the clutch and gas when idle or at low speeds. Any ideas?:confused:

Maybe problem with the idle bypass valve? What does the car do when idling in neutral? Car is new so its probably not clutch wear or fluids of any kind.

When idling at neutral, engine is quiet with no rpm fluctuation. It is interesting that this problem completely disappeared for a significant amount of time when the dealer replaced the VANOS. I appreciate the reply.