2004 Toyota Sienna Fuel System Other Power Train Problems

I WROTE TO TOYOTA SEPT. 7, 2007, CONCERNING AN ACCELERATION PROBLEM WITH MY 2004 SIENNA MINIVAN, FOLLOWING MANY VISITS TO THE DEALER TO EVALUATE AND FIX IT. THE THROTTLE RESPONSE IS DELAYED, IN MY CASE; IT LAGS DURING INITIAL ACCELERATION FROM A STOP, BUT MORE IMPORTANTLY, IT LAGS WHEN IMMEDIATE ACCELERATION IS NEEDED FOR PASSING, AND ACCELERATING AFTER SLOWING FOR A TURN. THE FACTORY REP WHO RESPONDED TO MY LETTER SAID THE DEALER WOULD REEVALUATE THE PROBLEM. THE DEALER REP DROVE THE VAN, EXPERIENCED THE SAME PROBLEM, AND CONCLUDED IT WAS A "QUIRK" OF THE CAR, THAT COULD NOT BE FIXED UNLESS, PERHAPS, THE COMPUTER CONTROLLING THE THROTTLE WAS REPLACED. THEY WOULD NOT DO THAT UNLESS A RECALL WAS ORDERED, HE SAID. NEEDLESS TO SAY, I THOUGHT THAT WAS THE FINAL WORD, UNTIL OTHER PROBLEMS BEGAN TO SURFACE WITH THE "FLY BY WIRE" SYSTEM IN TOYOTAS. I DO BELIEVE THAT THE ELECTRONIC THROTTLE, THE THROTTLE POSITION FEEDBACK CIRCUIT, AND RELATED SENSORS ARE AT FAULT, ALL OF WHICH ARE CONTROLLED BY THE COMPUTER. I ALSO HAVE OTHER CARS WITH ELECTRONIC THROTTLES, AN ACCORD AND A TOWN & COUNTRY, AND NEITHER HAS THAT PROBLEM. NO ACCIDENTS HAVE BEEN CAUSED BY THIS DAILY MALFUNCTION, AS I GUESS I HAVE ADAPTED MY DRIVING STYLE TO IT, BUT DON'T YOU THINK THERE IS A SYSTEMIC PROBLEM HERE? THE INCIDENT DATE IS A CONTINUING DATE, BEGINNING DURING THE FIRST YEAR OF OWNERSHIP (2004) UP TO THE PRESENT TIME. *TR