Hard starting And blue/white smoke on idling

[Rickymoo123]

Hi I bought a skoda Octavia vrs 2007 diesel a month ago and it's hard to start from cold but once started is fine alittle rough sometimes when idling and when your parked or sitting at traffic lights a a white / blue smoke strong smelling comes out the exhurst I've had the car checked mechanically and there is no problem with the engine. when the mechanic was checking he noticed a weld on the DPF filter could this mean the car has been turned and maybe haven't deleted the egr valve and dpf filter off the ecu??? If anyone has any idea would help thanks! Ricky 

[Kenny130pd]

You might be better posting in the Octavia owners section.