The knocking noise can be heard when I am in neutral or park around 2000 to 2500 rpms. If I goose the engine to this rpm you can really hear it>>>

Yep! Same here. We're definitely hearing the same noise.

I really don't notice it when I am driving, except when I listen carefully at a slow acceleration>>>

When I'm driving, I'll notice it right before 2nd gear kicks in during slow acceleration...which occurs at about 2k rpms.

They can not tell me the exact cause of it without taking apart the engine! They checked a few common things that it could be and it wasn't>>>

Do you know if they dropped the oil pan and checked the bearings?

I wonder how many more people have this problem with this engine and just don't notice that it existS???>>>

I remember when I posted the last thread a while back, there were several other 5th gen owners who said they had it. Basicially, they were given the same list of things it 'could' be. In any case, I haven't heard of it causing an engine failure yet (knocking on wood) and at 143k miles, my engine is still going strong. I'll still go ahead and set an appointment with the dealer to have them diagnose the car for the heck of it and see what they say about it. Definitely good to know I'm not alone with this!