was there any update on this. I am having a very similar issue - no code 13 - just running on 3 cylinders. Missing are 2,3,4,6,7. I have redone the timing 3 times. see post here.
http://www.clublexus.com/forums/ls400/475994-92-ls400-wont-start-after-waterpump-timing-replacement.html...