When you start your car, the smell coming from the exhaust can often smell like rotten eggs. This can happen especially when you start the car from very cold. It can also happen after fast acceleration or extended periods of idling.
The problem is high amounts of sulfur used in the gasoline. It does not affect the engine or durability of the car, it is just unpleasant.
Sulfur is normally removed during the refining process but the EPA regulation of sulfur in gasoline differs from state to state. When high sulfur fuel is burned, there is a chemical reaction in the catalytic converter causing the sulfur to oxidize. As the vehicle is driven this will reduce and the smell will disappear.
Switch to a different brand of gasoline. After driving for at least 100 miles, monitor the reduction in the odor. Try to avoid excessive acceleration or short trips and long idling times. Keep in touch with the EPA and gasoline websites to check sulfur content.
