Noise from engine

Is there enough oil in the engine? If the oil is not low, you probably have a problem with your valves, in which case a trip to the mechanic is in order.

Low level or incorrect oil, but internal engine wear also possible. Zee

What grade of gasoline are you using, regular unlead or premium. You should be running at 3.5L or 3.8L V6 so premium gas should settle a ticking or knocking sound. Also, using a good gas additive can help as well.