BMW Repair: fuel systerm, gunk, fuel lines

Question
hi i have an automatic 318 ran out of fuel girlfriend put about a pint of petrol in she thinks was unleaded but got to the station put 10 pound worth in and it is still unning ruff eg not fully acclerating when i come to stop it stalls doesnt give me any power foot flat down and it takes ages to go any were  

Answer
Simon,
 You likely sucked some dirt or debris into the fuel lines by running the tank so low.  There is always some dirt or suspended solids in the fuel that we put in our tanks.

 You might put some injector cleaner in the fuel and try to break down any gunk, and change the fuel filter.

 Hope this helps,
 Josh