[jhautz]

check to see if your ESC is plugged inot the reciever with the correct polarity. I had mine switched once, it did the exact same thing you are describing, and it took me an hour to figure it out. I know... Its silly but I tought Id throw it out there just in case.

For that matter... Check the polarity on all fo your connections just to be sure.

If that doesnt work check all of your solder points. Give the soldering points on your plugs a good tug to make sure you dont have a bad solder joint somewhere. Sometimes they look good but really arent.