I've had this happen before, but not in the Viper. About two months ago, a friend went to New York and left her new 6-speed Maxima at my house. 1st time I went full throttle, I let my foot off the gas and the damn pedal was stuck to the floor, scared the heck out of me as I was on a normal city street and those Maxima's are pretty damn fast for a normal V6 sedan, hit the brakes and the pedal popped up. Happened everytime I went full throttle, except when I dropped into 3rd on the highway and went through the gears w/o the pedal getting stuck at full throttle on my way to the airport to pick her up. It didn't get stuck on any mats or anything, just at full throttle the pedal would stay there.
Told her about it and she went to get it checked, but of course the dealer found nothing wrong
off topic: that 6 speed Maxima suprised me with how quick they are, car was awsome on the highway and for a n/a V6 it had ton's of low end torque, (obviously not Viper like in power lol).