Raise timing and start power a little and see if your cogging lessens. If not, you probably can assume that there is some cogging with little throttle.
when i got it (used) it was on high start power and normal timing. i lowered it and cogging didnt change. anothe guy at the track has same complaint with his.
the track is really a small 1/10 scale indoor track. on a 180 turn sometimes if i slide the car and it stops at the apex it will cog trying to start out.
my 808 with mmm and 1512/1.5y is smooth as silk in the same turn