Thanks to all for the advice. I changed the jumper on the pololu branded driver and that altered the distance. However, for some reason, the Pololu black acted differently, not sure I can describe how, but, not good. Picked picked up a controller at microcenter (sainsmart) and, with the jumper in the '16' position, I seem to be back in business. It is interesting that everyone seems to point at the same a4988 spec sheet. but perform differently. I need to do more research.