I am inheriting this row home once the owner passes. Its bought and paid for. Been updated to have 2 bathrooms we had the house fixed and inspected. Ac unit newly fixed and cleaned, But this smell has been going on for years and it only happens when no guests are around, meaning if they dont think we have company but my.out of town guest didnt have a car so they assumed they could make smells I guess. And it stops when police or fire department comes.