Old Car Smell: What Intoxicating Scent Was I Huffing?

I just randomly remembered some olllllllld random shit and was wondering if any car gurus out there could help me identify what likely poison I was getting high on in the 4th grade.  My mom used to have an Oldsmobile Cutlass Supreme... think it was an '88 model.  It was old & broke down when we bought it but we were poor, okay?  Anyway, whenever we'd turn the A/C on, for one brief glorious second, a smell would emanate from the passenger side vent that would make my eyes roll back in my head with pleasure.  I'm talking a powerful burst of craving for more of the smell along with a significant "high".  (I'd call it orgasmic but I was nowhere near an adult, so we'll stick with "high"). 

I never could tell if the smell itself was actually "good" or if I was getting high on some chemical & had come to associate the two, but either way it was absolutely heavenly.  I'd try to "smell" it for longer than a second but it was gone, only to come back the next hot day when the A/C was turned on.  It was like one inhalation's worth, then boom--gone.  Didn't happen with the heater or any other function of the car.

Interior of two '88 Olds Cutlass Supremes w/ offending air vent circled

As far as I can recall, it had a somewhat musty, sweet smell that wasn't too strong but BOY did it make my whole body melt with intoxication.  For a brief second, anyway.  I'm horribly allergic to mold so I don't think it was that.  I refuse to go and huff antifreeze, Freon or any of the other possible culprits due to their deadly effect so I'm at a loss. 

I've never experienced that "first burst A/C high" in any other vehicle but that shitty Olds.  It would break down on us everywhere we went so there was likely a lot wrong with it, plus I thought being an older model there might've been different refrigerants or other chemicals in it that have since been banned/phased out.  That's just a guess though.  

I know cats will drink antifreeze to their deaths because it tastes "sweet," which also makes it a popular poison.  This definitely had a sweet smell but not like anything else I can compare it to.  Oh, and the smell of gasoline gives me an instant migraine so it wasn't that.  It was not a harsh chemical smell--just sweet & literally intoxicating, similar to an MDMA eye-rolling effect.  That's the best description I've got lol.  

So I ask you, car geniuses of the world:  What intoxicating substance was I likely huffing through my mom's air vents in her '88 Olds as a child?