i just got an 06 gp gxp with 46,000 miles. when driving at a steady speed the rpm fluctuates 500 rpm. some times it does it almost all the time then sometimes it just does it every now and then. it doesnt jerk, its very smooth when it does it. you can hear the exhaust change tone, and see the tach fluctuate. i think its displacement on demand but i dont know. any ideas? i have a 3 month 3,000 mile warrenty and if there is something wrong i want to get it fixed while under warrenty.