[lnfletcher]

Its call positive feedback (through the pedal).
With these high torque, low weight cars, when a little fuel is given, it surges forward forcing the driver back into their seat with the result of letting off the pedal which in turns causes the car to engine break which causes the driver forward and in turn giving it more fuel and surging forward, forcing the driver back into the seat and letting off the pedal, and so on and so on.

Same thing happens on a 4wd truck in low range (max torque).