Ah, it's been pretty well documented that those people who lift cars on their children in emergencies aren't doing it because of "faith".
It's that adrenalin fight or flight thing.

I also wouldn't buy the firewalker thing. I know there is scientific documentation of meditative states allowing people to alter heartbeat, respiration, etc. that is related to healing and stuff. But I really think you are grasping at straws with the "faith as cause" thing here.