“If you feel a vibration either when pushing the accelerator or when coasting, these are often the cause.” “Any time you see your check engine light come on, or you notice a different smell or odor when you start your car, it is a telltale sign of a problem and should be checked out immediately. “ “Excessive smoke or a rotten egg smell coming from your exhaust pipe are signs that there is a problem with either a leaking fuel injector or a bad oxygen sensor. Any one of these components malfunctioning can devastate your gas mileage not to mention the performance of your car.” On top of good old-fashioned tune-up parts, there are many new products available to your automotive repair shop that are additives placed in the fuel and engine block of your vehicle. These products are very powerful and should only be used by a certified mechanic. They do a very good job of cleaning out your engine and fuel system from all the deposits that build up over time.