Tekin Rx8 problems

[silverfox]

Hi all
Running Pro4 4600 motor and RX8 in my SCTE It has run without a glitch for the last 6 months. Racing on Sunday and it only managed a few laps before slowing dramatically as if shutting down on thermal overload. The motor and ESC are cool to touch and the LED's are telling me all OK!
I've tried another battery, checked all the wiring, tried changing the esc settings (more current limit on) and everything else I can think of. The only thing different from last race-I have downloaded and installed the new Vegas software.
Anyone any ideas or come across anything similar?