I just bought a mp3 adapter? weird noises?

i bought an iconcepts mp3 adapter for my car. you connect it through the cigarette outlet and set a switch to a certain station so you can listen to your music. ex. 88.1, 88.3, 88.5... it also can recharge your mp3 or ipod because it has a usb hole on the side of it and also an aux hole. i use the aux hole. it works fine but i hear a high pitched noise coming from the speakers. i know its either coming from the outlet or from the adapter because i move it around while its connected to the cigarette outlet and the noise just makes a scratching noise. its kind of annoying because if i play my music loud you can hear the high pitched noise in the background. i was wondering if there is a way to fix this problem? the adapter is fine its just the high pitched noise is the problem. is there something wrong with the outlet? please help. and thank you in advance.