Will obviously bow down to the more tech people among us,

Have always been lead to believe 'sweet smell' indicates 'coolant', watching the video, it does (to me anyway) appear the same as if there is condensation/damp in the exhaust, seen similar after starting straight after a wash.

If it is 'sweet smelling', possible head gasket???

Certainly needs looking at, be it oil or water, something not right.

hope you manage to sort the problem whatever it is.


Edited to say, could it be no more than it needs a slight tweak on the map?? running rich maybe??