I have the 8" powered directly from my ITPS without any noise. I have my screen directly under my radio too, so while I don't have a solution, I can tell you should be able to fix it.
When my LCD is turned on I get noise through my FM stereo.
I have an FM modulator, but even with the modulator turned off I get noise if the LCD is turned on. When I run the sound through my computer it is worse.
I have also noticed it gets really bad when my wireless PCMCIA card is plugged into the laptop.
Has anyone else had this problem?
How can it be solved.
I have the factory radio in an '04 Malibu Maxx, the modulator is connected to the fuse box. The Lilliput is connected to the cig plug using the supplied Lilliput cable w/ egg thing.
The computer is connected to the same power fuse as the modulator using a car laptop power adapter.
A lot of installs in this forum use 12vlts from the DC-DC converter.. mostly it is because the grounds are taken from different point on the chassis - in your case sounds like you have a ground off the ciggy..change the ground - prefferably to a common one. good luck