I have a 3 year old gas furnace,It's a high eff.RUUD modulating type.In the last week we have noticed a gas odor coming from the vent outside while sitting in our hot tub about 10 feet away from the vent.There is no odor ,Or co detected inside the house.Is it normal for the vent to give off a smell of rotten eggs?

Thanks

No, this is definitely not normal. I would strongly suggest you call in someone to check for leaks inside and outside. I once worked where they had gas furnaces and you could smell the gas very strongly outside the building but not inside. When the gas company came to check for leaks the guy shook his head in amazement saying that he was astounded that no one walking by holding a lit cigarette in their hands or puffing on one didn't blow the whole building up. There was a leak in one of the connections on the outside of the unit. He had the proper leak detection equipment. You need to call in a qualified outside repairperson to properly check for the leaks in this system. The leak could make the unburned gas pool inside or outside your home in lethal pockets.

You can also suffer very bad headaches or lightheadedness from continuously smelling the unburned gas. You can also experience vision problems as well from this gas.