A jumpy throttle or a jumpy driver?

[Bratman91]

I am now on my third IS250 automatic, the first having been bought almost as soon as the model was introduced a decade ago. I find that, in comparison to the two previous generation cars, the current one is very sensitive as low speeds to throttle movement. At medium to high speeds, there is no problem but around town, where split second decisions often have to be made because of heavy traffic, I find it difficult to  make manoeuvres that involve, say, having to get into a busy roundabout, without the car almost jumping forward. It sometimes feels as though there are only two throttle positions - too slow and too fast, and that there is nothing in between. The throttle pedal doesn't seem sticky at all when testing it by hand in the garage. Of course, it may be me that is jumpy but I never had the problem with the two previous versions of the car or, indeed, any others of the many automatics I have owned or driven.  Are there any other IS250 owners reading this thread who can comment?