can you read live data? if so, check your pedal sensors on the 05 and post what you come up with. i havent cared enough to read any more about it, but awhile back i read that if one of the pedal sensors goes bad, or gets too far out of spec, the pcm will ignore it and use the other two sensors to triangulate the position of the third sensor via a series of calculations. i dont believe it will throw a code until 2 sensors go crazy. i would imagine the calculation slows down throttle response, but like i said i havent cared to really dig into how it works exactly.
i know i have one sensor that reads a bit more depressed @idle than the other two sensors