Prius (2004-09) :: 2007 Shakes When Braking Below 7 Mph

My '07 shakes when braking below 7 mph. Coming to a complete stop is never perfectly smooth unless medium to hard braking is required. My thought was that the MG2 is in creep mode even while my foot is lightly on the brake pedal, causing the jerking, but creep works properly while not braking.

The shaking is very steady, at about 6 Hz, the same frequency as the "popping" noise one hears when stopped at the light with the foot lightly on the brake; just enough to keep the car from creeping, but not mashed far enough to turn off the creep current from the battery. I take it there's two sensors on the pedal as well as a potentiometer. Could the problem be mitigated if the creep current were cut off at the presence of a foot rather than having to press harder? There is no shaking on a harder stop, only the slow ones.

Another thought I had was that the pressure pump itself is supplying the brake pressure to the friction pads, causing the pulsing. In a previous thread, we discussed why my pump was coming on so often. Perhaps a leak in the canister causing the pressure not to be buffered, and the pump itself providing the pressure.