Ok, I see that this issue has been asked two times before, but never really answered:

Break pedal arm and gas pedal arm shake..
http://www.scionlife.com/forums/viewtopic.php?t=4075&highlight=brak%2A+pedal%2A

Brake pedal has 0.25-0.5" left to right horizontal trav
http://www.scionlife.com/forums/viewtopic.php?t=29687&highlight=brak%2A+pedal%2A

It seems most Scion brake pedals have about a half an inch 'play' left and right. I guess it's normal... just feels a bit strange. Comments? :? RPM

My current car both the brake & gas do this. Asked a mechanic if they knew why. The answer or something like what I can recall.

"They move just a little for some what of a saftey reason. When you hit bumps or anything that can make your foot come off the pedal, this could cause a hazard. So the pedals have this little bit of give, so you have a better chance of keeping your foot on the pedal you need it on."

"They move just a little for some what of a saftey reason. When you hit bumps or anything that can make your foot come off the pedal, this could cause a hazard. So the pedals have this little bit of give, so you have a better chance of keeping your foot on the pedal you need it on."
Interesting idea... not a bug; instead a feature. Thanks chucksu, we're gonna miss ya. Anyone else care to comment? :D RPM