Aux jack picks up engine noise. on 2009 Kia Spectra

If I have my iphone, ipod, XMradio, etc. powered from the cars 12V power, and plugged into the aux jack, I have engine noise feedback. If the device is internally powered, no problem. Only when powered from vehicle power. What can the problem be and what can I do about it?

Asked by for the 2009 Kia Spectra
That's a tough one. I think your best option is to take it to the dealership--it's a brand new car, so you have no worry of incurring any costs. They are best positioned to have an answer--maybe even calling Kia directly is an option. The car is so new, few independent professionals are likely to have seen this problem.