I have a 2001 S4 that I got about 10 months ago. It is a Tiptronic with 84,500 miles on it. Here is my problem, when I punch it at about 40 mph or so, the car will be fine up until 4500 or 5000 RPM. Then it will seem like it kicks out of gear. It loses acceleration but the revs stay the same. As soon as it shifts again, the car will take off again. It does not do it all the time, but most of the time. I've been reading here on the forums to see if anyone else has this problem. I have not had the oil changed in the transmission. The dealership said not to about 3,000 miles ago, but I did not mention this problem at the time. It has just gotten worse lately. I am taking it to the dealership to run diagnostic tests on the transmission later this week. I am hoping there will be a cheap fix like an oil change or something because I cannot afford a new tranny. I'm graduating high school and going to straight to college, the car will most likely be sitting in the driveway for some time if it is the transmission. Please help as soon as possible.