I have the same problem as noted above. One thing I did notice is that when the surging starts, if I try to shift to 6th manually it isn't smooth at all, and seems to jump when shifting. I was wondering if it was a 5th vs 6th thing as another poster was...and when shifting manually seemed to be a problem, I thought that may be part of the solution.
I took it to the dealer, and they couldn't reproduce it, as usual...so no fix.
It only took 6 times for them to fix my steering knock, so maybe I just have to keep taking it in.