Originally Posted by 135i_vs_
What's your average MPG for daily driving? It will give a good idea how much you push your engine, as others are saying to drive the motor hard at times to clean carbon.
Maybe a separate thread should be made where we each state:
Mpg on the car
Avg speed on the car
Carbon build up issue yes or no?
I think those are some of the key factors which are relevant to this issue. If anyone can think of anything to add to this list. Let me know I'll start the thread tomorrow.