Well i have a buddy at Jay Wolfe Toyota, another at Ackerman Toyota. Wow, more STL people popping up here.

 

Well the accel position sensor does not directly send signal to the throttle body like on older cars. On this system it has to go thru the ECM that sends the signal to the throttle body. In the tech world this is called the "mother may i system". So the lag is going to be there, because the ecm takes into account how fast your going, and how the car speeds up so it can open the throttle accordingly while, delivering the spark, and the fuel needed for the speed. If he wants a diagram, it wont hurt none to look at, but i dont see were he can make any changes. based on how it sets up. What probably happens with the aftermarket system, it changes the values of the resistance once pedal applies for a quicker response. I might have lost myself here a bit but hope this helps. Or if it dont make sense, i will fix it.