Capacitors could be worn out.

I called Castle on this and they came up with odd excuses first as well, once I told them it worked great and instant amazing burn outs when first buolt they said it's most likly worn out Capacitors in the ESC.
My sensorless 2200 and Castle Mamba has InsAne! power when I first drove, then sat in storage for many years, and now it is stuttering. I have since changed capacitors but have not yet check the ESC settings or the XPS Lipo 6S 4000.