[redfox]

It's called the "bunny hop". There is nothing wrong with the car. It's your right foot that's the problem. With a sensitive throttle, when you press the throttle, the car's front end raises slightly, causing you to press a little harder than you intended to. So your body retracts your foot a little, causing the car to slow down, and the front end drops. Then you subconsciously press a little harder and the cycle continues until the sensitivity is eliminated, which can be done by switching to second gear, or slam on the gas pedal. To prevent it don't go beyond "sport" for throttle response.