There has been known CI/lag issues with some servers latetly, alot of people feel your pain. Some things you can do that might help if it's on your end:
- Turn off modem wait ten secs then repower, sometimes the modems get currupt data in them and can cause connection issues. Also you can unplug modem and hold power or reset to drain any residual power that is hiding in there prior to plugging back in.
- check drivers are up to date ( this week alone ive had new drivers for my cpu, gpu, and HD audio ) so chances are you might have the same updates.
- If you have installed new drivers recently then roll them back one at a time and test the connection between each driver roll back. If none are the culprit then re update the drivers again.
- make sure any uneeded programs or processes are turned of like uTorrent or steaming to name a couple. Also some media server software can lag you out or CI you during game play, I had CI's for two weeks and couldn't play, then me and my flatmate did some trouble shooting and testing and it turned out to be some media server software that he had installed. As soon as we disabled it my connection was normal again.
- Have you changed any hardware? Alot of parts go together, but that doesn't mean they will run to thier best if paired with something that may be lacking grunt and ends up hindering pc performance.
- Run a system scan with anti virus, also you can run software to check your registry and remove any entries that relate to deleted software etc. CC cleaner is good and free and easy to use. There are other freeware as well.
- Update PB with PBsetup.
- Uninstall COD4, reinstall, repatch, update PB. Don't forget to save a copy of your profile, maps and mods folders located at C:\Program Files (x86)\Activision\Call of Duty 4 - Modern Warfare, then after installation delete the folders of the same name and replace with the saved ones from the previous install and bobs your uncle. ( do them one at a time so you don't forget where it's supposed to go)
I hope one of those sorts you out, or you find another solution soon, it sucks having continuous ci's. Good luck!