One day when I started my car, I was hit with a blast of sweet smelling toxic fumes from the AC vents. I could still slightly smell it while the car was running, but it was strongest immediately after starting the car. This continued for several trips until I finally took it in for service. The service people at the dealer couldn't smell the fumes, so they kept my car overnight to try smelling it themselves in the morning. In the meantime they gave me a bright red Mustang convertible to drive around for the day. They confirmed the problem the next morning, removed the interior dash, did some welding, and put everything back together. I never smelled any problems again and the whole ordeal was free.