ES350 Acceleration Stalling

[Acceleration Stalling]

Purchased a Lexus ES350 in December 3016 with only 17,400 miles on it.

It has a stalling/hesitation problem when accelerating.  It is not constant.  It is intermittent.

When I push on the accelerator pedal the car simply will not move.  Pushing pedal all the way to the floor is initially unresponsive, but then the car accelerates quickly.

Taken it to dealer and they say that the car is OK.

Concerned that the lack of accelerator pedal control being unresponsive and then accelerating could cause a major accident.

Anybody else having the same problem?

[jamesm182]

Could be the throttle position sensor but would have thought the dealership would have picked up on that?