Or it's got Diesel in it??
Sorry no, you can't find a fault from that description.
It could be a multitude of things and you have to go through a list of stuff to check so you can pin point the fault.
Kev's probably right or it could be as bad as the cat being blocked.
If you google the fault there will be DIY sites that run you through the checks you can do one by one to save some money.
_________________________
2011 Focus 3-door Zetec 1.6 TDCi.
Previous <img src="/images/graemlins/stemo.gif" alt="" />s - 2006 Panther Black & 2007 Red. Gone and quite forgotten <img src="/images/graemlins/lol.gif" alt="" />