Standing behind the car, its almost like putting your nose over a gas tank. Plus, their is black smut on the bottom of my bumper. Every time I wash my car, it comes back within a day or two.Also when you punch the gas, there is a little bit of black smoke that comes out of the exaust. Ive checked my spark plugges, and at the end of each plug(where the thread runs out) its black. The bar that over laps the electrode is a greyish white color.