I have had severe post nasal drip which corresponds with when I got my new car. I noticed a couple times that there was a bad smell when I started it up but then it went away. It seemed to come through the vents also when I turned the heat on. It seemed to go away but now it's back and since nobody has been able to help me (ENT) steriods, CT scan etc... I wonder if it could be making me sick. I'm taking to the dealer this week.. but my question is could whatever it is do this to me? and should it go away once the car is fixed? Could this have caused permanent damage of some sort to my nasal membranes I just want this to end!
one way to test is to rent a car for a week or two and see if your symptoms go away. maybe request one of the older rental cars as opposed to a brand new one. if you suspect your car, i would do it immediately.
Is it a brand new car or a used one? If it is new, you might be reacting to some type of chemical. Maybe if you air it out you will feel better. Also, you might want to get the air filter replaced, especially if it is a used car. You might have allergans in your heater/air conditioning system.