Hi flying the Archer DX with the Diesel engine over the summer I have experienced that the engine sometimes do not run as expected, it happens both in flight and just after takeoff, it is engine roughness ore misfire as it is like flying on 3 cylinders, from ground it is visible due to more smoke. It normally disappears after 15-20 seconds.
...what happens is just following the POH checklist and the recommendations, that don’t make the roughness disappear, and yes when the engine is smoking like that it is a matter of air / fuel, an that is controlled by the FADEC, my interest are more on the wastegate vs FADEC that might not play that well, we just have to let the Continel come to that conclusion