Unstable connection

almost every game if not every game that i play online rivals or live events basically anything against another player says i have unstable connection and then i get the yellow or red icon at the top and my ping goes all over the place. I have 2GB wifi and have an open nat and get 500mbs a second on my console. is anyone else having this issue? i seem to not be able to fix it whether i reset my router or fiddle with settings on the xbox itself none of it seems to fix it.