(G) starting

hi i have a 1,2 mk1 97 punto 60s the problem i have is starting the thing.from cold no probs after a short journey the engine will turn over and over but not start eventually it will start on 2 then 3 then all cylinders this is accompanied by a sulpher type stink it happens most of the time but if the car is left for half an hour or so it will start no probs.when turning the car over it will try to catch and start but if i touch the throttle to rev it it dies instantly also when it eventually starts the engine will race at about 4000 rpm for about 5 mins and sometimes on tickover the revs rise and fall apert from that everyting is fine any ideas?