Hesitation on Alfa 159 2.4
Any suggestions would be appreciated. I can't take it to a specialist because I don't know of any in SW France which is where the car lives.
The car starts and idles perfectly, it accelerates pretty well with no real kick until 2500 revs though. Occasionally I notice a plume of black smoke on full and hard acceleration. The car runs fine 98% of the time but on motorways at cruising speed there is the occasional "glitch" or hesitation which goes again almost immediately. It seems to be worse when cruising up an incline. The car has been to a main dealer twice for investigation without them finding any faults. Driving me nuts now as everything else is absolutely fine
The car is a qtronic which had a new engine 20k kilometres ago, has had a new EGR 10k ago, just had a forced regen followed by a 1600 kilometre trip on pretty clear motorways for the most part. I have cleaned the MAP. The car has been in a main dealer and shows no error codes on their machines..twice. I have run it on premium diesel and two fill ups ago used a diesel injector additive on filling up. All to no avail.
I am wondering if it could be the MAF?