A couple of problems which appear to be related (i.e. they showed up at similar time). Would appreciate some insights into what the cause(s) might be.
1. When cold, car won't always start. If it does, it will stall when put into drive (it's an auto) or when revved (stops when the revs drop back). Re-starting then difficult - sometimes have to switch off and wait for several mins before re-trying. When it does eventually start, there is a fair amount of black smoke. Doesn't appear to be a problem when engine is warm.
2. Engine appears to cut on overrun at high speed (70mph ish) and takes about a second to pick up on reapplying the throttle. When it does cut back in there is a big cloud of black smoke. This happens fairly infrequently at present, but is getting progressively worse.
Mechanic who looked at it thought it might be something to do with main injector pump control.
Anybody come across anything like this? Any ideas welcome.
Many thanks

Yeh the fuel pump or fuel pump relay is the usual suspect on TDIs, can be difficult to diagnose though to the the intermittant nature of the fault when it first presents.

I would run the car past the eyes of say 3 seperate garages and see if their is a general opinion based on experiance and a "live" viewing.