Strange shudder/flutter at partial throttle accel

I've searched around here and have yet to read anything about it, BUT.... turns out the GenIII Prius guys have felt it.

I stole this quote from a Prius Chat thread, but it describes it almost perfect. Acceleration issue - PriusChat Forums

"My car does this about 50% of the time when turning a corner - I know exactly what you mean!

Usually, the scenario goes something like this:

Approaching a turn. Decelerate using light braking to ~30 km/h.
Execute the turn, releasing the brake and getting on the accelerator, lightly.
Accelerating at a constant rate, 2/3 to 3/4 of the way up the HSI, and completing the turn.

At this point, at somewhere between 30 and 60 km/h, there's a definite, defined "flutter" coming from the engine/powertrain/motors. The gasoline engine is already on at that point, so it's not the engine "starting up" (I know what that feels like!).

It's one of those things that there's no way I'd ever be able to describe to a tech - or they'd just look at me and scratch their heads. So I don't worry about it. But, it's like a minor chest or heart palpitation - it makes me nervous, every time it happens."


I can't quite duplicate it on demand, but it seems to get worse with colder temps. Anyone?