To cut a long story short, I recently got my Bravo (1.2) its winter service. Straight after I drove 300 miles. Over the past week during acceleration the car chugs/kangaroos/jolts until the revs are over 2000, after which the car performs fine (this applies to all gears). I checked the oil level and found that it was over the max level. So after draining some oil out to restore it to a normal level the problem still remains. Whether the oil level and the problem are related I don't know, but any diagnosis would be appreciated.