Something is Burning

Since then I have noticed that each time I drive the car and park I can smell something burning!!! Last night i saw a very light smoke/vapour as well but it dissipated very quickly and the smell stuck around for just about 10 minutes after which it went away. I took the car in over the weekend and the dealership held it for 4 days but they could not get it to happen.
Any ideas on what this could be?





