Are you using a Novak Motor? which one and what are your motor temps? sounds like you got a bad motor or someting wrong in the sensor I know the Havoc will thermal at 150* F im not sure about the GTB but the other ESC your using too??? I would contact Novak first before buying another Speedo I know a few racers in VTA that use the GTB and never had a problem and thats all Novak motors