The head work was Gomer but he did use the "Timing tool" though not sure if he knew how to set timing right. Its water under the bridge now. The second mechanic has BMW experience and also has the BMW Diagnostic computer. He did say that he has cleaned the Vanos and checked the seals. We noticed the following:

When the gas pedal is pressed right away, we see that ECU is sending ground and some value for the "Vanos exhaust ref position" and "Vanos inlet ref position".
If there is a delay in pressing the gas pedal, there is no ground and there is no value being sent for "Vanos exhaust ref position".

I think I have the following options:
1. Take it to the "stealership"
2. Pay this mechanic to redo the head again
3. Replace the TPS sensor (The symptoms are relevant but no code)
4. Rebuild the VANOS

The vehicle is worth about $6000.00 in normal running condition. So don't really want to spend thousands fixing it.