96 GXE (automatic), 126k.  Front end brakes were recently redone,
calipers are free & clean too.  axles/CV's have both been done in the
last 12k miles (drivers side done probably 5-6k ago), so i dont
suspect them.

there is no predictable frequency to the knock/pop;  it can happen
with brakes on, off, though it doesnt seem to be tied to applying or
releasing brakes.  it can happen at low speed on smooth or bumpy
driveways/parking lots, or medium speeds on various road conditions.
it also doesnt seem to be tied to steering angle, as it can happen
while turning or driving straight.  ???

I have investigated links in the front end and cant find anything
obviously wrong (torn boots, free play of wheel/tire  when jacked up,
etc).  Somehow i remember people saying maxima's had problems with
upper strut bushings going out and causing similar problems, but would
they sound like that under those same conditions?  The rack/boots on
it are in OK condition, though there is some fitting underneath the
rack that looks like it has been sweating just a little, though no
appreciable fluid loss has been noted.  Steering wheel feels smooth,
on the ground and with both wheels jacked up.  Also, i realize
balljoints, tie-rod ends, and struts all may be suspect simply from
their age (they are all original, 126k miles).  ??

any ideas or has anyone had similar problems?

Also, when ball joints or tie rod ends are getting old, how do you
know they are at fault if the boots seem intact and they dont have
perceptible play when rocking parts all over?

thanks a bunch,
Matt