My 08 Cayenne S runs great going through all the gears.When i'm on the highway in say 6 gear when i give it more gas it feels like it's sputtering. If i give it a lot of gas it will downshift and be fine it seems to do that in 4,5,6 gear when i'm just driving along then give it more gas. Any idea what it could be? Read another post and the problem was the 02 sensors,I have no lights on or anything so I'm not sure what it could be. Any help would be great. Thanks