Is my boxster broken??
 

I have a 2002 tiptronic Boxster. When I'm driving down a hill, my speed slowly decreases but rpms goes up. Im not stepping on the brake or gas pedal. Just letting the car glide but the rpms....omg bothers me. When I drive a bmw, toyota, honda etc, (all automatic, same circumstances, same hill, same everything) the car just rolls, gets faster due to gravity and momentum and the rpm stays around a constant 1k. Also i noticed that this happens on the freeway too. When I'm going straight on a declined road, my car slows down...like what the....shouldnt it gain speed instead of losing speed?? Is something wrong with my tiptronic boxster?? or is that normal??

If you take your foot off the gas, the computer says you want to decelerate. Since it's a programmed automatic it will do just that. If it needs to down-gear, it will do that. Seems normal. I think mine does that.

The gearing is set up in these cars very short. If you let off the car will decelerate, the lower the gear the quicker it will do so, but yes almost even think of it like regenerative breaking in modern electrics, if you let off it breaks, stay on the gas just barely and your mph should stay the exact same.