[Joe Ford]

Fully charge the pack and make sure it is taking a full charge. If you have a dead cell in the pack that could cause it. A bad connection between the cells can do it as well. Plug into the computer and re-flash the software on the ESC, then re-calibrate the ESC to your radio (full throttle, full brake, neutral...in the manual). Unplug all the motor to ESC connections, and see if any of them are easy to pull apart. If one is, put something into the end of the connector and spread the legs apart a little. Also, try another battery.