Hi,
check my topic, I had speed jumping problem and I added capacitor to all my boards to smooth out speed-jumping
http://ecomodder.com/forum/showthrea...5-a-21984.html
Maybe you could try to remove that capacitor near input pins and resistors - it has 103 written to it. Probably you have so many pulses (normally pulses/mile is between 4000 and 10000) that capacitor is smoothing pulses to steady voltage.
Meelis