About 3 or so months ago a really rotten sour like odor just started in our living room. I have had the carpet and furniture cleaned and I have used Febreeze on it every day and it WILL NOT go away!! Shortly after this we noticed ants in the living room also. They are the Odorous House Ants that make a really awful smell when squished and they like to colonized under carpet and in floorboards. We have had an exterminator out and he sprayed and baited and he thought they could be the cause of the smell with us walking on them under the carpet. We went on vacation for 3 weeks and when we came back the smell was gone, but by that night was back, after we had been home walking around for awhile. I have not seen any for a week or so and the smell is still here. Anyone else ever had this problem before? Could it really be the ants? Any suggestions on how to get the smell out of the carpet? I am desperate at this point!!!!