I have a Fiat 500 Lounge 1.2 on a 09 plate. I have an issue where the idle speed seems to increase when I am in traffic. It idles well and then increases for no reason and then goes back down to normal. I thought it was the climate control but in the cold weather it still happens. Sometimes it makes the steering wheel vibrate. It feels like some sort of fan, but the car is not hot. It can sometimes happen as soon as I drive off and stop at a junction. If anyone can help me diagnose this issue that would be great.