I made a left turn at a T-intersection, and tried to accelerate to avoid the cars coming from left/right.

I felt a jolt and heard a clunk right when I gunned it. Is that the nanny kicking in?

 

Not sure what a nanny is unless that is tranny which I doubt is the problem. I remember I heard a clunk coming from the rear like in the trunk when accelerating fast from a stop light in the IS350. It only happen once but did look in the trunk for anything loose. In the IS350 If you punch it from a standing stop in will snap you forward very quickly, the GS is a little more mild in that respect. If you have the ML it sets in the bottom of the trunk right side under the removable floor panel. Check to see if it is secure.

 

electronic nanny.

it's definitely mechanical, not anything loose. I doubt there's anything wrong with a 1 week old car.

I wonder if that jolt from the rear is from the traction control kicking in...
I've never felt anything like it, since I've been driving FWD cars all my life.

 

Besides the clunk,

has anyone felt a dramatic pause in power when flooring the car out of a turn.

When I do this, I feels like the car is taking a deep breath before moving forward..That has always bothered me but the dealer says its par for the course.

 

Actually just today I was thinking the exact same thing, making a U turn and flooring the gas pedal, nothing happened, power delivery came only after the wheels were almost strait again, I'm pretty sure it's the "nanny".

Just to be sure try to disengage the traction control (long press on the center console button for non hybrid model)

 

Definitely traction control in all of the above situations. IMO, the traction control is way too agressive and practically cuts power completely when it kicks in.