These are not the normal symptoms of throttle hang. It sounds like you throttle is "sticking" or a valve or sensor is out of whack. There are two areas that could be causing your problem. The Idle Air Control(IAC) valve could be sticking or need to be replaced and/or the Throttle Postion Sensor could be shot.
I had this problem and a recall took care of it. I could cruise down the road at 50 MPH and not even touch the gas. Very dangerous!!!!! The recall was for part of the accelerator cable causing it to stick before returning to its "resting" position. Yours sends more like one of the two above mentioned things though.
