our 4450 when it is ideling sometimes it is kinda rough. or when i  take it from a idle to about mid thottle it lets out a bunch of white smoke but it goes away.  Then it seems to smoke quite a bit just when your driving it and not pulling it heavily. i seen what looked like some oil or fuel that had leaked at one time when i was using it inbetween the exhaust manifold and the turbo gasket. I need to check the turbo what im getting at is if i was wondering if i have some really bad injectors or and turbo thats about ready to take a major dump or something else that i cant think of thanks>>