Toyota Repair: 2004 Toyota Sienna accel. hesitation problem, electric fuel pump, hesitation problem

Question
I was a line mechanic for a dealership years back and had my own shop for 18 years, so I have some experience in mechanical problem solving. As I have read, my new 2004 Toyota Sienna (1k) isn't the only one to have a lull in the acceleration at certain times.  I notice a lull when softly accelerating out of a uphill sweeping curve, same problem when accelerating off of a uphill residential speed bump.

Question, could the roll over saftey sensor be cutting power to the electric fuel pump momentarily. Giving me that sense of a lull or hesitation. Possibly also causing the transmission to be indecisive in gear selection.  Your input might help Toyota with a little problem that they so far have no solution for.  Thanks

Answer
There are two service bulletins from toyota that may relate to the condition you are experiencing.
TSB TC007-03
TSB EG029-04
The first one involves recalibrating the ECU, toyota refers to it as a shifting enhancement procedure.
The second one is to repair a possible lean run condition, this should actually trigger the check engine light and give a PO171 or PO174 dtc.
I would recommend taking it back to the toyota dealer and have them check to see if either one or both apply to your Sienna.