Well, after a LOT of digging around it does looks ZPC is the route to go. I'm have been traveling so I haven't done it yet, but based on this TSB:
http://4runnerclub.com/i/4r_files/fs...SB-0020-08.pdf
it's required anytime you do an alignment or chassis components have been replaced...
I replaced EVERYTHING front and rear and did an alignment, so I'm certain this is the issue now.
I just need to find a level spot to do the actual calibration. My driveway is level left/right, but I need to jack the front of the car up about 4 inches to make the running boards level.