Carseat smells funky???

Anyone else's carseat smell gross.  My DS has decided this will be where he spends the majority of his time (naps, bed, etc) so it's starting to really take on this weird smell.  I've taken off the fabric or vinyl or whatever it's made of and washed it and also clorox wiped everything down more than once.  i even got in the nooks and wiped all the dried out spit up.  It looks brand new and was used only by my DD.  After washing and air drying that seat, I thought it would be fresh again, but it still smells gross.  Anyone have any good ideas as what to put on?  I've also tried Febreeze and that works for a while, but then the smell comes back.  FYI, we have no pets or animals!