Recently when we start our car, it idles rough. It started for the first time about 4 days ago. It doesn't do it every time you start it either. Today, when started (for the 7th time) it did it again. This time however, it was idling around 500 rpm and was acting like it was going to die. You could also smell fumes inside the car (not sure if it was exhaust smell or gas smell). I shut the car off and waited 1 to 2 minutes, restarted it and all was fine. Also, it is only at start up idle when it does this.