Ghost on my accelerator

I have a 95 Dodge Ram 2500 12 valve cummings diesel. It’s a manual transmition.

My odometer is blinking and when I put the clutch in after putting it into gear once or twice, the accelerator acts as though I’m pushing down on it-the fuel pedal literally sinks without my foot on it. It’s as though a ghost is pushing the pedal to the metal. What the Heck is going on? I checked the accelerator spring and cable and they are fine. Thanks so much,