Engine not running properly

My truck starts up fine and idles fine. When I am at a complete stop and accelerate normally the engine chugs and sputters and there is no power. I keep trying to feather the gas pedal it will eventually get up and go. But if I am at a complete stop and stomp the gas to the floor the engine runs fine. She takes off with a quickness, no sputtering or chugging. Also while I am driving down the road, say at 55 MPH, the engine will suddenly lose power and sputter and chug for about 30 or so seconds. If I keep feathering the gas pedal it will suddenly be fine again and take off. Any ideas would be greatly appreciated.