Hi, First post as I’ve been trying to identify what could be causing a rough idle issue I’m having with no luck so far. The car is a 2011 A1 1.6tdi. I’ve investigated most of the common possible causes, EGR, TB, filter etc. VCDS shows no fault codes. When the engine is warmed up I’m seeing revs dropping erratically at idle and the engine sounds like it’s about to cut out. With more revs the engine runs absolutely fine and no problems whilst driving. What’s really strange is that I just realised that when the headlights are turned ON the car idles perfect and as soon as I turn the headlights off again it idles rough as anything. Normally this is the other way round! Does anyone have any ideas?