I have the same thing... I was optimistic that changing out some suspension related compontents would correct the "popping and knocking" sound, but so far I have struck out.
I have changed out the steering rack guide, my LBJ's, and my outter tie rods. At this point about the only thing left I can think of are the inner tie rods and have been contemplating doing the entire steering rack as that comes with the rods.
Honestly I only hear it when I wheel my Runner and it is very annoying, but on the other hand I am not taking it out every weekend... so the impact is a half dozen times a year. Regardless if I could narrow it down inexpensively I would love to.
Hopefully this thread elicits some other ideas...