2005 Lexus ES 330 2005 ES330 doesn't shift smoothly

Hello,

I have taken my car to the Lexus dealer and an independent mechanic both of whom say there is nothing wrong with my car. No codes are in the memory and nothing found on diagnostic scan. And of course it never acted up when we had folks look at it. It shifts very roughly between 25-35 MPH and sometimes on takeoff it does the same thing. Also seems to be more frequent the longer it's driven. I'm not sure if it's a tranny thing or a fuel line/accelerator thing. The Lexus dealer said there's an electronic sensor instead of a timing belt mechanism that tells the car when to shift and that it will eventually "learn" my driving habits. It's been a year and has acted exactly the same the entire time. If the electronic piece is removed would that "reset" it and stop the rough shifting?

I really hope you can help.

Many thanks,

Karen Bickers - Lousiville, KY