Sometime the rpm goes up when I coming to stop or braking in highway. Why would this happen?

 

Peter - might I suggest you setup your signature (look under "userCP") so it adds the year/model of your Cayenne. Once again you're asking a question which would get much more intelligent answers if people knew what year/model you're talking about. I gather from your other post that it's a NEW Cayenne. If this is happening - GO SEE THE DEALER. It's not supposed to happen (well - maybe in a Hybrid - but even then...)

 

Sounds like it's rev matching? Which mode are you driving in?