Fuel Problems

[cuddlydave]

Hi All, Ok i have a 1992 316I E36, andf when the car is started from cold the car smells badly both inside and outside of petrol, I have checked the fuel lines ect and thgere is no leak anywhere, ALSO my millage to a gall has dropped to around 10 to the gallon, Finally i have noticed that around the exhaurst at the rear of the car there is black soot asif the car is running rich.
PLEASE ANYONE GOT ANY IDEAS AS TO WHAT THE FAULT MAYBE.
Thanks for reading and any help you maybe able to give.