My 2001 A4 has benn driven mostly city miles with no problems until recently when we took the car on a 400 mile trip. While returning home I noticed the tranny seems to take much longer to shift from one gear to the next. Once the car has sat and I drive it in town again it shifts fine until it hits the highway for a while, then fine again in town. Also seems like the engine idle speed jumps up slightly when this happens. Any ideas?