i recently changed the oil and noticed that the oil filter was dry.

Is the oil light on?Possibly low oil pressure?

nope, the oil light isn't on

I would be concern about the knocking i have seen oil filters when i changed them seemed like there was no oil in them.Where is the knocking coming from?

sounds like it is coming from the valve cover.

Get a oil pressure gauge and check the actual oil pressure.Did the knocking start one wasnt there the prevous day?

it started a couple of days ago when i was coming home from work, when i got home i checked the oil and it was low, so i just changed it since it was time.

How low was the oil?

i believe it was around the add a quart mark.

If this is a 4 cylinder the filter is mounted facing down so it drains normally when parked.

So when you topped the oil off it didnt get any quetier?

nope, its still making the same noise, i was thinking it might b the oil pick up tube, or maybe the oil pump, but i will check the oil pressure with a guage this weekend.

These engine are notorious for sludged up engines. I would remove the valve cover and see if it's sludged up.

Thats a great idea wrenchtech.

yea, it is a good idea, but i replaced the valve cover gasket, b/c it was leaking and everything looked fine in there, there wasn't any sludge build up anywhere

Back to checking the oil pressure manually.

Try removing the sump and checking the pickup for any blockage.
The mesh on the pickup blocks easily on 5sfe toyota engines with sludge etc.

Ite a lot easier to check the actual oil pressure first thing start guessing.