Hi Floyd
After re-reading your solution, I dont know if I fully concurr (but that doesnt mean to say it will not work!).
My feeling is that it is a fuelling problem and it feels (i.e. I think, without enough evidence) like only three cylinders are working properly when this happens and when it does happen, I am not using the clutch, i.e. I can drive at maybe 1000 rpm in first for about 10 seconds or so and then as the throttle is depressed slowly, I get this jump.
Your description makes it sound as though they are all like that, which I cannot believe. To me, the problem is dangerous.
I have a tekmate system, which I have tried to use, but it is not particularly helpful as it only feeds back parameters every three seconds.
This Friday, I am off to see an injection specialist who is going to wire my car up to his test equipment. The things I will be looking at are the injector durations for all 6 cylinders (hopefully - if he can do that) and the lambda sensor operation (O2) as my attention is now turning to one of the lambda sensors on the exhaust manifold (I dont know which) as that seems to be the only thing that could change the operation of one bank of three cylinders (which is my guess). It is possible that one of the lambda sensors is faulty and does not operate properly until it is hot, driving around with low load (first gear - low revs) possibly doesnt get the sensor hot enough.
The EEC will only detect a fault when a sensor fails out of range, it is possible that the lambda sensor is failing in range.
In addition, I have printed down all the emails and digest postings which I have read, of which ALL only seem to affect the 330, and I will be taking them to the dealer and asking him to call BMW in Germany as the problem is not "in my head" and my car is not unique.
I will keep you guys informed.
Nick