Constantly underboosting with quite a bit of high RPM FLKC - I'd get it checked out. In the mean time you can use ATR to knock down your base timing between 1.5 to max load and 4k to redline about 3 deg. That should stop the knock until you can get it checked out.
If you find that dropping the timing doesn't help at all, then you can start thinking about something rattling or an oversensitive sensor, but I don't think that's your problem. That looks like real knock to me (high load, high RPM, consistent). The cause could be anything from a failing fuel pump, clogged fuel filter, bad MAF readings, lousy fuel, etc.
That's the worst place to have knock, you need to get rid of it ASAP.