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 ...
We had similar problem until we realized that our MaxxAir fan was working so well that it was drawing in cig smoke from other campers and they weren't that close to us. Took a few days of airing out and some room freshener to eliminate the problem.