Check the ohm readings from the throttle. On yours they should be 0 ohms at rest and 5K ohms at pedal to the floor. move it very slowly through the range and you should see the numbers change smoothly in the correct direction. If the readings are jumping around or exceeding 6K, you need a new throttle. My 97 was doing that, I am mid-way through replacing the potentiometer on the throttle pedal with a modern MCOR.
Rule out if your throttle is bad. If it is, then figure out exactly what you have, like a V-glide. multistep pot, etc. and then find a replacement, if possible.