This is a long shot but it's what was wrong with my TT that was smoking like the turbo seals had gone bad. I ended up with a hole in the pressure side of my fuel rail rubber line. It caused my Z to run lean under hard acceleration and as the hole increased in size to smoke even at idle. So check your fuel system and pressure coming from your fuel pump. A bad fuel pump, clogged fuel filter, dirty injectors or a leak in your fuel system can all cause you to run lean.
