Good question, I can't know for sure, and I wasn't watching the tach. It felt like a power dip, like either the transmission paused in some false-neutral between gears or there was a dip in fuel delivery. I'll see if I can catch the tach next time and watch for a rev change.It is surging or is it the transmission nit knowing what gear it wants to be in? Cause mine does the same, but my thought is, we aren’t giving it gas and ROM’s don’t change change, my thought was transmission not knowing what to do at that speed.