Maybe a “system adaption” after battery replacement.
https://www.mycarspecs.com/replace/toyota/sienna/2006/base/replace-a-car-battery
The gas pedal sends electronic signals to the PCM which then tells the throttle body how far to open
throttle plate opening and closing. In order to open and close properly, the computer must know when the throttle plate is fully closed. Some car makers have a self learning throttle body re-learn procedure. In those 2006 Toyota Sienna s, all you have to do is turn the key to ON and leave it there for 30-secs. without starting the engine. But other car makers have a complicated Hokey-Pokey procedure that requires multiple brake pedal applications, along with several key on/off cycles. Still others require a factory scan tool relearn