RE: Futaba S 3003 Servo Flutter???
That sounds exactly like a bad connection with the extension wire. I just saw something similar on Sunday at the field. A defect pot usually shows problems around the center or trying to find the center, but if it is deflected and it bounces, then that sounds like a bad connection. I use HD extension even on my 12" or 18" wires and only have 6.0 Volt batteries now.