So I've noticed my 2009 A6 3.0 TDI V6 is pretty noisy when setting off, or when feathering the throttle at a low speed, say 30mph. It sounds like a "normal" diesel, like i'm driving a Peugeot or something. At about 1.8k rpm (or when I put more load on the engine by adding throttle), the clattering/diesel noise stops and the car is smooth as silk with plenty of power - it sounds great. But this is now bugging me, to the point where I was worried I had no oil in it and had to check despite it just being serviced fairly recently. It's also very very slightly hesitant when first pressing the accelerator to move off. Come to think of it, it is more pronounced when the ambient air temperature is hot - it was doing it today and it's almost 30C. Anyone got any ideas on what the problem could be? No check engine light, no codes, no power loss... Thank you for any help you can give.