salva1996 - It sounds to me your radio is glitching when your engine is on (assuming that you have nitro). Check to make sure you don't have metal to metal contact. Check your clutch bell to ensure it is not touching your flywheel (in addition to what gs-sonic-racer mentioned). How about rx/tx battery? Sometimes, glitching can be caused by bad set of crystal. Also, do the radio range check (with your engine off).