Hello.. got a humming or vibration noise coming from our Fridgidare(FGF337BCF) Oven. It starts after the temperature gets up to or around 350. It definitely sounds like it is coming from somewhere around the burner tube. There is no discoloration in the flame from the burner at all. It is just a steady humming or vibration and goes away when the oven is turned off. Any help would be great. Just want to make sure it is safe with Thanksgiving coming up next week. Thanks