Okay, I ran into this problem just this past week or so.. I changed my oil about last month, and my mileage was about 89k. Next thing you know, my engine is making this clicking, or knocking type noise. It would be louder at idle, and more discreet at higher RPMs. So i check my oil, and it turns out to be PITCH
BLACK 
. So Now i change my oil AGAIN, with thicker stuff.. flushed it out, and added Lucas oil additive. The engine now runs smoother, but the clicking, or tapping, or whatever sound i could use to describe it. My friend says it sounds like I need to change the lifter, or there's something wrong within the engine. I really don't want to take my vehicle to Ford, because so far, everytime i go there.. i end up paying a [censored]-load, and another problem arises within the near future. I searched the forum, and it came up with a leaky fuel injector valve, or even a whole engine replacement.
Another thing is, that before i changed the oil, the sound would once in a while stop for a short while, and come back on after a really soft thud.. or rather tap from the sound of the engine.
Thanks for all, if any help...
Ren
