Just purchased and 03 A4 3.0. First time owner and love car. However, I knew before purchasing that maintaining it would be up to me keeping it up to date and here I am. It has 136k, taken care of well and later today will take the car to Auto Zone to get checked due to "check engine light" just popped up. Just wanted to know from others experience and knowledge about what is expected of this around the mileage....? Any information would be great.