elderone

I have a really strange problem with my car in that when I go to start it at work, very often the engine will start but the revs will not go to idle and the oil and battery light stay on the dash. This will go on for a few seconds then it will kick a load of smoke out the back and the engine goes up to normal idle and lights go out. This is obviosly not right and ford can't find the problem. What I can't understand is maybe something you clever peeps might be able to help with is why it only ever happens at work after being there for 7/8 hours and never once has it happened at home after being parked overnight or in fact never at all at home. I have seen someone else on youtube with the exact same issue with it only happening at work and at cold temps. Really confusing!!