[suicideneil]

Firmware issue probably- downgrade back to v1.24 or whatever you were running before, recalibrate the esc to the radio, and try again. If the motor won't respond to small inputs then I doubt it's the traxxas connectors acting as a bottle neck- there are some wild rides around here fitted with them & deans plugs ( same size essentially ) and they work just fine, though checking for broken or cold solder joints is worth while.