When you start engine bad bad smell comes thru the vents, sometimes lasts two minutes other time ten to fifteen minutes. The smell comes with or with out A/C or heater on, or just fan. You have to ride with windows open, even in 90 degree weather. In the beginning when this started it wasn't so bad but it is getting worse. Brought to the Dealer and they suggested changing cabin air filter, which is behind glove box. This was changed about two weeks ago and it seems to be worse.