My 2008 2.0T with 7000 miles seems to be running a bit rough. I have only had the car a month and i have started to run it on super unleaded which may be part of the problem. When i put the heated rear window on for example, the idle speed drops - as normal but the car seems to idle really rough then. Also the car jerks very slightly when i press the accelerator pedal very slightly after just coasting along. Sometimes the car seems to serge very slightly in power also. I have noticed that the idle will often drop to about 500 revs when coming to a standstill with the clutch pressed, before recovering to about 700-750 revs. Sometimes the revs will drop to 500, then go to 1000 and then settle to about 750. I understand that these engines dont have an idle speed control valve but a stepper motor on the throttle body. Any idea if this is normal or not? The car has never cut out/stalled.