159 Cruiser and
AO Silver Member
Join Date: Jul 2012
Location: United Kingdom
I tend to get around 43-44from mine, (though it dropped when I had EGR/ MAF issues). Also note that although I do most A-road/ motorway driving, it doesn't really get over 40mpg til about 10-15miles. It also drops off significantly over 75mph (who..me!?).
As for the black smoke, diesels tend to do this under load, or with issues...Turbo, injectors, or the intake system.
As far as I am aware, EGR issues don't tend to give a lot of mis-fires, so I would also double check your MAF and MAP sensors (it seems a lot of EGR issues are linked to the MAF). If these are mis-reading they might make the car run rich.
Also stick in a bottle of DPF cleaner in the tank, if your car is throwing out black smoke, then there is a lot of soot passing through it, which might block it (reducing MPG), may have happened when you had the mis-fire issue, and not recovered.
159 1.9JTDM Ti and Giulietta 2.0 Veloce
ex: Punto 55s, Golf Mk5 1.4FSi, A3 (8P) Sportback 2.0TDi SE, A4 (B8) 2.0TDI S-Line, 306 HDI Meridian