I just got a pioneer deh-p4800mp today and installed it right away. The unit powered on and played flawlessly. However when i turned the engine on i noticed that there was a high pitched squealing coming from the speakers. I turned the volume down but the squealing remained. I revved the engine and the pitch of it went up even higher. The only difference i have from my last cd player is that i have a second rca line running along with the first one to my amplifier. Does anyone know what might be causeing the squealing or how i should go about getting rid of it?