l have a bmw 319(93) , after l drive for a while, and start from stop ,l can feel the engine shake a little. but stops when l pick up speed.

Also l can smell fuel , just a bit. but l dont think its related to the engine shaking.

ya me too, l have a 1994 325. l think it is after 20 minutes or so on the highway and that the engine is a bit noisier because the oil has been flying everywhere inside and when you roll to a stop it drips down resulting in a higher hum

the fuel smell is unrelated you might have a leaky gasket

Two possibilities.
One is a vacuum leak. This is usually due to the 'flying saucer' on the PCV system failing.
Part number 11 here:
http://realoem.com/bmw/showparts.do?model=CA53&mospid=47490&btnr=11_1408&hg=11&fg=15
But it can be due to weak vent or vacuum lines or the intake boot.
The other problem is the engine mount itself may have failed. If they look wet at all they have lost their fluid and are not damping the vibrations.