All of the photos so far have not been of a 98-00 LS 1UZFE VVTi engine, so here are some pics of my engine, and maybe someone can point to it on there. After rummaging through my PDFs, I did find some relating to this. I kind of thought it might not have one either since I couldn't see it either, but it looks like it's hidden if I'm looking at the PDF right.
I had my starter replaced on my '91 (300k mi)and this problem developed; very annoying but I persisted with my shop and finally the shop determined problem to be vacuum leak at intake manifold. Replaced gasket of intake and all fuel injector ports for good measure. No longer have problem. I had thought the computer was faulty but shop owner never thought that, he always said it was vacuum problem.