My 929 is doing the same thing re: surging, but I am not having the issue with the display going off.
I thought it was going to be fuel filter, so I went into the tank and found water/rust in there, and the old filter was full of rust. Swapped it out.
When I finally got it all back together yesterday, I filled it up with fresh fuel, and went for a 5 minute ride. It was still bucking like mad under full throttle, but seems OK under very light throttle?? Actually much worse than before.
Please post back if you find the issue, and I will do the same.
I think I have just found my problem...15 minutes after posting this
It looks to be my dumb fault after re-attaching the main high pressure fuel hose back to the pump assembly...
I just looked at it with the tank installed, and it looks to have a huge kink in it! I found this after it wouldn't start for me after sitting overnight.
It looked like it may have weakened in that spot now, as it kinks as soon as I try and bent it a little, and no fuel flow.
I'll just replace the hose and be done with it! Unfortunately, it is now full of fuel, so a bit heavy to lift!
It certainly wasn't like it when I removed the tank.
So as a suggestion, I would check the fuel filter anyway. It cost me AU$106 for the filter, and would have taken about 40 minutes to do if I wasn't farting around. At least it is good insurance if it does not fix your issue.