i've found over the last couple of months, sometimes the engine will make a pulsing sound like someone keeps reving engine and lets off teh pedel and then repeats this lots of times. I've found that sometimes reving it hard will stop it. But this noise can be a little embarasing in car parks.

Injector/air pressure sensor/throttle oh the joys of Fiats!

Start with the easier things first,try resetting ECU then clean throttle & carry out re-learn phase,good luck

Iv been told that Fiat Brava / Bravo suffer from throttle body issues which can cause them to rev high or stall for no reason.