Surging is a bit of a misleading term I think, I don't think it is really surging. I don't know how else to describe it though.
It's not like a TP cut or anything like that where it feels like you have hit a wall. It's much more subtle. It's like if you were driving along, and you just tapped the accelerator quickly. It speeds up a little bit, slows down a little bit, speeds up a little bit, slows down a little bit, etc. Very minute, so hardly registers on the speedo at all, but you can hear it and you can feel it. Only ever while cruising, and only when it's cold. As soon as you put your foot down or decel quicker or the engine is warm, it doesn't do it.