Over time and miles, your car might start to slow down. It might not accelerate as quickly as it once did; the engine may not run as smoothly as you remember, or the fuel economy may dip—but ...

Over time and miles, your car might start to slow down. It might not accelerate as quickly as it once did; the engine may not run as smoothly as you remember, or the fuel economy may dip—but ...

My Mercedes-Benz people put an “injector cleaner” in at each service, despite no recommendation in the service manual to do so. Is this a useful thing to do? The truth is no one can define the results ...