Propane-like smell coming from car.

my2004Z

Have you actually given your entire exhaust system a visual inspection? On my previous Z (350Z) I had a thick piece of plastic bag, something a contractor would use, get stuck to my catlaytic convertor and after I removed it and scraped the residue off it still smelled real bad for several weeks. I finally lifted it up and did a real thorough job removing the hardened melted plastic. It was hard to see because it turned brownish black thereby camoflouging it with the rest of the exhaust parts. I'm glad it didn't start a fire.