did you tyr switching channels? sometimes that helps. if your car has a top deck, did you try putting it (reciever or speedo)there? i know some1 who had to put it (speedo) up there so it wouldnt glitch. or maybe its just JR . just about everybody who runs jr at my track glitches, so...
maybe you should invest in a 3pk if you can get one. its pricey, bet well worth the money