Ford focus cutting out when at a stand still?

have had problems with faulty ecu has been disconected by my mechanic but has been driving ok, then last three days have been driving about and when at a stand still at traffic ligts has been cutting out then today have tried to start it and wont start sounds like it has ran out of petrol have had it recovered to house and the mechanic has said there is no spark fom the leads does this indicate coil pack has gone please help am at end of tether with hthis focus have had nothing but trouble with one thing and another