Accellerator do not open to full when driving

The car uses electronic throtle control. At idle, when I accelerate, it does not stall nor does not do anything at idiling. But when I start driving the car on high way, when the speedometer riches at 80 and still I am pressing the paddle to down, it does not respond. The paddle does not use cable. It is wireless. Please I have not done any repairs now, so please help me to solve this problem. Thanks