Bi Na Ri X

When I play MW2 on 4D1, i usually have a ping of 60-80. Somehow, without visible reason, my ping often goes to 999 for about 5 seconds, and I start moving weird all over the map. This happens whenever I play on the map Terminal. My FPS are about 90, so this is not the problem. Also, I checked for apps running in the background that could cause that lag, no results. Can anoyne help me?