speed wiper contact & board
Your description of the throttle problem is classic speed wiper contact & board contact failure.
Have a look before the fire starts, lol. The 'pzit' sound is the sound of arc welding the movable contact mounted at the end of the throttle linkage to the stationary speed selection lugs.... hope that makes sense.
http://www.buggiesgonewild.com/attac...n-img_3298.jpg http://www.buggiesgonewild.com/attac...n-img_3301.jpg http://www.buggiesgonewild.com/attac...n-img_4888.jpg
http://www.buggiesgonewild.com/elect...tml#post618591