300 Tdi

Hi, Can anyone help?

I've got a 300 Tdi fitted to my ninety, it's a former disco engine.
It starts fine, doesn't use any oil or water and is pretty efficient on fuel. However on start up it's pretty smokey (white!!!). This lasts until the engine gets warm, however continues when I deaccelerate at certain revs, even when warm. On start up also it seems to give a slight misfire!!!

Any ideas, would be most appreciated.

Could be extra fuel burning up and a misfire type feel suggests maybe an injector issue?

Or it might be water suggesting a problem with the head gasket or cylinder head. Common problem on 300s unfortunately