GMC vandura throttle problem

[merkur]

I have a 95 Vandura 3500 box van. I was a ryder rental van originally. Has 75K original miles and always very reliable. Last week after starting and warming up the throttle ceased to work. The pedal has tension and cable is hooked to carb. It rotates properly but the buterfly does not open. It almost seems as if both items were no longuer connected. I can idle back and forth but no throttle response. Any sudgestions are welcomed.
Merkur