I brought a s40 I noticed smoke coming from driver side of engine noticed more when sat at traffic lights then today I was sat with my foot on the accelerator idling to see if i could hear anything all of a sudden the engine started tapping and losing power and was shaking wildly I turned the engine off and back on and it was idling really bad but I drove it round the block and it was fine again still smoking not really bad but noticeable help please.

 

Was the temperature gauge right in the middle (assuming that's the normal position on your car)?

 

yes the car hasn't over heated at all

 

with the smoke I thought it was coming from the exhaust but the engine started shaking like mad and losing power then calmed down so not sure now

 

Check your oil for any signs of "milkshake" on your dipstick or under your oil fill cap. That would be signs of coolant mixing with your oil (a bad thing).
And I can only suggest seeing where the smoke is actually coming from - it's going to make the diagnosis a LOT more accurate.
Also, was the tapping a mechanical "metallic" noise, or maybe just because of the engine banging around when it was running / idling so poorly?

 

the smoke was a fault on the dpf so got a new fuel particulate filter fitted and a clip fitted to stop the deisel smell got it back yesterday but it still misfired not bad but when you put foot down feels like it's missing fuel??? and yes the clicking sounds like it could be tappets this car is a nightmare it looks nice but I've had it two weeks and been nowt but hassle.