still have a whistle/hum after regen valve

[mipstien]

I have the dreaded whistle from the evap system coming from the fuel fill area. I replaced the fuel vent and the regen valve but at speeds that are cruising with a constant rpm the hum comes on. does not do it during accel or coasting. It also seems to be doing it at nearly any rpm. 2k-4k common to be stuck at for any amount of time while driving and it will start to hum. It never does it at idle and it isn't nearly as annoying as it was before I replaced the regen valve.

There are no cel codes coming up and not even a possible fault showing up. everything is clean. The car is running currently better than it ever has, minus the embarrassing noise it makes from that area.

I don't want to just bandaid this sound I would prefer to figure it out.