My 2003 2.0 Petrol Duratec developed a real bad engine rattle today, has anybody else ever had similar problems to this or know what could be causing it?

Very rattly at start up and you have to hold a rev on her or she will die out, also very rattlyy under load and putting out white smoke from the exhaust but when at 50-60 mph it seems to be ok with no loss of power.