when im in park or idling for a little bit,the rpms go up and down about 2-3 hundred rpms and it will do it appr. every 15 seconds or so,but not everyday,its unpredictable,
egr maybe
If you have not already done so, I recommend that you clean the back side of the throttle body and butterfly plate. Good time to install the Billet Technology oil catch can also. http://www.billettechnology.com/#!__page-0_copy1
I cleaned mine at 32K and 56K miles, then installed the oil catch can. Totally fouled with crud both times.