A6 estate TDI keeps kangaroo in

[Scotty dog]

 Hi can anyone help me I'm driving my Audi A6 estate TDI sometimes it will kangaroo as is going along then black smoke will come out and then it will stop and pick up again it keeps doing it  regularly 

[Trevor]

Wouldn't even hazzard a guess without running a scan on the ECU first.

Could be a range of things causing the poor running fault

[Steve Q]

Is it manual or auto? Could be an issue with the gearbox. What revs does it do it most? 

As trever said best thing to do is get it plugged into a diagnostic computer