why not try hooking it up to a dvd player or ps2 or something while its still in the car. Use the same cable that your computer is running the signal to it. I dont have a screen but that would certainly be my first step in this situation. Also might look if everything is clear w/ ps2 or dvd, then just immediately switch to the carputer and see if the signal weakens again.
there are two criterias that is most likely the problem, bad cable, or something with bad grounding...
checking with a dvd player or something isnt a bad idea.. (for checking the cable) ... but to find out if it could be any of the external components (.. usb devices.. etc.) that is making the noise, then he has to just disconnect everything and just go from there....
thanks guys i'll give it a try
its really hard to work out of my dorm room...not enough of the right tools
I'm going home next weekend and I'll be spending some time on trying to fix it, i'll keep ya'll updated
I just ran across the exact same issue with my new carputer while bench running it. It turned out to be the fans in the Plexi Carputer case; they must be emitting interference to the video card.
Currently I am trying to isolate the power source for the fans so currently I have no solution - unless you disable your fans ;-)