I think I've got a problem or a start of a problem with my 1.8 mk2.5 focus tdci.
When I put the engine under load, I'm getting more black smoke than usual, not excessive amounts but it's noticeable.
I haven't had any problems with lack of power, everything seems fine in that department but I have got a drop in mpg.
I've usually always got between 45-48mpg on average over a tank yet the last few tanks I've been getting under 40mpg even though I'm now driving more conservative due to the arrival of my baby daughter 3 weeks ago.
The car is an '08 plate 1.8tdci focus zetec mk 2.5 and has done about 48k miles.
Any ideas what could be causing the increase in smoke/drop in fuel efficiency?
Any help is appreciated