Interference with Savox servo - any ideas please?

[AntH]

Has anybody had any problems from interference from Savox servos? When I operate the servo it causes the car to glitch and jump forwards. Originally thought it was because I coiled the long lead that they come supplied with, I shortened this and it still did it. Then I replaced my KO Esprit 2 40 meg radio gear with some Futaba 2.4 g and it still does it... Any ideas? Thinking of getting an Associated servo now. Speedo is LRP SXX.