If I had to guess, I'd say he's hitting it around 3k, as that's where it starts to make a dramatic rise. I've been known to be wrong before though.
Also, Hal, do you have a breakdown by RPM that shows your AFR? I would guess that would tell you whether or not it's going lean in that area. If it's not going lean, then I would guess that it's a dyno malfunction like has been said before.