Hi, My Fiat Sedici with the 1.9 diesel multi-jet engine is playing up always around 1500 revs. It will tend to lose power, then pick it up again, then lose it causing a short bucking bronco effect. Only does this at lowish revs say 2nd gear, once up to speed it drives just fine. Any ideas what might be the source of the problem? your thoughts appreciated.

EGR valve clogged?
Air flow sensor?