Do you get server disconnects? One night my isp was having problems and my ping was low but games were laggy as hell as you describe. There were a few random disconnects.
It turned out to be a problem with Hyperoptic
No, I haven't had any disconnects during gameplay. I have had 1 disconnect from the main battlenet servers and that was yesterday following a completed match. I was back in to the main game very quickly though.
Yesterday I had a lazy day and so decided to perservere with CoD. I played from around 11am till 5pm with on and off breaks for lunch and other stuff such as to rescue a bird that had hit a bedroom window and was lying on the patio stunned and likely nursing the mother of all headaches!
Hours of play and I had bad ping and weird lag all day. Bottom of the scoreboard mostly, with some moments of reprieve but not many. It's like I cant get a match below 60 ping at all. So I'm guessing I am getting euro servers all the time. Very regularly in 80-100 ping servers too. A few times the lobby system timed out and had to make another pass to find a server.
I played a few more games last night between 10:00 - 11:30pm and whilst my ping was still rubbish the weird lag wasnt as bad. I was able to get kills and was getting a score that's more reflective of my actual ability. I'm not the worlds best player but neither am I bottom of the scoreboard with .50 kd player either!
So it seems liken it could be the time of day. Perhaps my isp is traffic shaping to cope with demand. Perhap cod servers are struggling with demand. Perhaps a bit of both.
But my actual FTTC connection seems rock solid so theoretically it shouldn't be my ISP.