Ping Spikes But Only In Team Fights

This issue started 2 or 3 weeks ago and I'm at a loss when it comes to fixing it. Everything runs smoothly when I'm farming in jungle or whatever. But the second I enter a team fight my ping shoots up to 3,000ms (or more), everything freezes for a few seconds, sometimes it says I disconnected, and when everything goes back to normal a few seconds later I'm dead and my team is flaming me.

I've tried reinstalling several times My internet speed is fine 35-40 Mbps upload, Download close to 50 Mbps. latency is normal GeForce is updated Nothing every buffers on my internet, Netflix, YouTube, etc. Windows is up to date. Firmware is updated on my modem.

This only ever happens when engaging an enemy champion, and is worst in team fights with several people. I cannot play the game because of this, I just end up feeding.

Help!