CoD bo2 strange frame rates

[caim1231]

So I got on Call of Duty: Black ops 2 today, and I have had an issue for a very long time, and that is very rarely does the game actually run smoothly. Once in a blue moon, the game is very smooth, everything seems fast, im hitting my shots easily, but then after I die, everything slows down, kills are taking way longer, im less accurate, and im dying faster. Its not my ping or fps, I usually run at 90 fps, and my connection varies a lot so I cant say much about it, but even when I have good connection I still get these problems.