Problem displaying nintendo wii graphics

I have a new LG LCD tv, and it works perfectly, except that when I am using my nintendo wii (either with component cable or regular av/cable) it sometimes has problems with the display. In certain regions of the screen the picture will go grainy with a lot of the pixels in the wrong color - mostly green and red. In a game like lego star wars it happens very infrequently, but in games like resident evil 4 or zelda where the graphics are more involved it happens almost constantly (except in menu and transitional screens). I don't really think this is a problem with the tv, since it is perfectly capable of playing DVDs and television (both HD and SD) with no problems at all. I have also played PS2 games with no problem. It also seems strange that the wii would have any issue since it was working fine with my old Samsung SD tube tv. I have tried using pretty much every combination of tv picture settings and wii settings, but none of them seem to make any difference. Any ideas?