Well for starters, the control knob shouldnt be off, it should be on as in turn on that damn a/c...hahaha...lol....JK, Anyhoo, I coulldnt resist....please excuse me on that one.....lol. In all seriousness tho, I think your big problem is that someone got in there and pulled all your insulation and sound deadening material out of your car. Your interior definately needs all that stuff in there in order to keep that thing from becoming exactly what it is now, a giant pressure cooker..!!!!
The stuff could have been removed for a number of reasons but more than likely what happened is that the backing was smelling very bad from a mildew problem that happened over an extended peroid of time. These cars have a tendency to leak either from sunroofs or rear quarter windows that dont seal properly to worn out window gaskets and too many trips thru the automated car wash not knowing about any of the above and thats just for starters. I dont want you getting the idea that foxes are as bad as gm products when it comes to leaking so dont get me wrong. These are general maintenance issues that when addressed individually over time can be handled quite easily and relatively inexpensively with the exception of the quarter windows perhaps.
The point here tho is that you need new backing and insulation for your carpet. I dont know where you are financially as well as where you are in your fix up plans but there are a couple of ways you could proceed. One way is to scour the local pic and pull and find yourself a stang like yours that has its carpet/insulation/backing setup intact and snag it. The only catch to that deal is that you have about a 50/50 chance or maybe a bit less of finding your carpet in a car that has had its windows rolled up and to make matters a bit more complicated just for funs sake, finding it in better shape as in it hasnt had the same problem and is loaded down with mildew and funk.
Another way is to go thru a website like Latemodel Restoration Supply and buying a whole new setup including new carpet, padding and insulation. That would be a sweet, sweet deal although more expensive and usually at the tail end of someones fix 'er up list of things to do cuz it will get trashed in the process of doing everything else. Know what I mean?
So there ya go. Just a couple of ideas to ponder. Hope I could help some.....l8r
