A heating vent in one of our upstairs bedrooms is blowing out a terrible odor into the room. We have a gas furnance and this problem is only in this one bedroom -- no other rooms/vents in the house. We have tried many types of deodorizers but nothing works... We pulled the vent plate off but can't locate anything in the vent that would be causing the smell. Does anyone have any ideas on what this could be???? Our home is 5 years old.