We have the strangest odor in our TT...it smells like an ash tray! (That's my best description.) We bought our TT in March, obviously used from CampingWorld and we were able to go into it and look ...
Skunk will do it....and quite possibly mold. Also, I bought a used car that came off lease. I am an ex smoker and can smell that yuck miles away. The car smelled like it had been cleaned; maybe from detailing, but no bad odors. Three months or so later, we both clearly smell cigarette smoke in the car. The dealers have stuff that will cover anything up.