Gas Pedal

[dubois]

We have a 2009 Mazda 3 2.3 Hatchback automatic. I have noticed that when I first hit the gas pedal and the car starts to speed up(between 1st and 2nd gear) there is an audible spring sound that we can hear and feel through the gas pedal. This only happens once when we first start up the car and accelerate. When the car is shut down and restarted we get the same thing again only once(1 springing sound that can be felt through the gas pedal lightly).
Does anyone have a clue with what might be going on?

Any help would be greatly appreciated...

Thanks