I just bought the car and is my first audi. It has a miss in it I know how to find that but it also has a hissing sound. I noticed it while sitting in a drive through. Any thoughts on what it could Be? I will also mention that when I try to take off I have to take it easy or it will just bog out and is very jumpy if I try to get rpms above 3k. Again any help would be great thank you