This only occurs when I've been driving the car for a good few hours in traffic.. A few hours 2+ - traffic = stop start city driving. Also happens at idle (leave a friend in the car and run into a shop) This has been going on for a few months now.. The car is perfect other than this. The car does this 60% of the time that I'm driving it in the above conditions, I'll be driving it on A roads for 30 mins then get to a town and be in stop start traffic. Whilst I'm on the Aroads and any other long roads that don't involve town driving the car will happily sit at 80-85 on the temp gauge, no problems at all. When I get into a stop start or town situation after 10 or so minutes the fans will kick in, a slight smell of coolant that's strong enough to smell inside the car with the windows half open. Following this the car judders, shakes and is generally very rough this usually lasts a few minutes and is followed by jerkiness when trying to pull away and hesitance. The car never dies.. Idle never drops past 700 or so and its perfect once cooler and out of the traffic.. ( the temp only ever goes as high as 90) The jerkiness and hesitance is like the car wants to go but quickly decides its not going to and then it is.. If that makes sense. Anyone care to diagnose what's wrong with my baby?