some thing to think about (not sure if this step was taken but I only skimmed) you may want to see if your TV's manufacture has away of flashing their firmware (I had to with my Sony Bravia) mine was doing some thing similar to this with my HDMI when ever I switched inputs Sony told me it had to do with HDMI and power output. but upgrading the firmware via the USB input hidden in the back solved the problem right away.
as for Vizio some people may have had better luck than I but I was one of the first owners of one of their products and was very unhappy with the product. The power supply that was inside the TV burnt out after 14 months (two months past the warranty) so of course to repair the unit it was going to cost 200+ bucks depending on how many hours it was going to take to replace. A friend of mine in PA had the same problem with his so they lost my vote.