I would suspect the coils rather than anything else. If you can run to two new coils, swap the suspect ones with the new ones and if that fixes it, its fixed !.
MEP's guide (above) should help if you want to avoid any unnecessary expenses upfront.
If you later find you really didnt need the coils then you could probably easily off-load them on here or ebay. Carparts4less, eurocarparts,or gsf are best for prices on these. Fiat ones are something over £50 each.
I had two coils go on one day on my 1.2. completely without warning, the car was driveable but only just. I later had a third fail, one dark November night and the fourth on the way to trade in the car. The more experienced users say replace all four. Once you've established the real cause of your problem , you may think that a sensible action !