Mini Cooper S R56 Black smoke on cold start

Hi,

I have a 2007 MCS R56 which has started puffing a bit of black smoke when started from cold. If i give it a few revs, it seems to be worse. It reminds me of a diesel car when they give it some. It only seems to be for a minute or two though as once it has warmed up, it seems to stop. The ends of my exhaust are quite sooty.

Has anybody had this problem before or know what might be causing it? I have had no end of problems with this car and this may well be the final straw. :-(

Any advice/assistance would be greatly received.

Thanks,

Darren