07 m8 top end bog

First ride out today from about 5000 feet to maybe 6 or 7k. She ran good from the truck. Pulled hard 8k revs about but about 2 miles in it started to bog on the top. Stoped and checked plugs mag side was pretty light brown. But pto side was slightly darker. Ran decent in the mid range but as I went it progressively ran worse but on the way back it picked up down towards the truck. What could be causing that? And when I would come off the throttle it would go down to 11 or 12 hundred rpm but would pick back up to 16 or 17 hundred. Some of the time if it was bogging I could get off the throttle and back on and it would pull for a sec and then fall on its face again. Is the motor hurt from the slp pipe? When it was apart I went through and polished the exhaust port and took some of the rough spots on the intake ports. Ran good when I gave her some heat cycles in the shop.

problem solved

For future reference i found the problem. The tube that hooks into the ecu to tell it barometric pressure was full of ice. Cleaned it out and she runs like a top pulling hard at 8grand all day.