I believe I had a problem like this once, only it was a two stop, the car would yo-yo like your car then would eventually mlt. I found that the 5 volt power from the IN2 contact was not making it to pin X on the power board. there was a loose connection at the terminal strip on the side of the controller where the board rack swings out. I still cant find the ULD terminal on my print, I know I have seen it on a print, any body Know where it is or what it is for?