I'm currently in the middle of my 90K service for my 2000 Lexus GS300 with the Toyota 2JZ-GE engine. I have the timing belt off and I was going through the "inspection" potion of the service. The Lexus service manual says that the time belt tensioner should have a protrusion sticking out of it (and it does) that measures 8.0 - 8.8mm. Any more or less than than and you should replace the tensioner. Mine measures 10.1-10.5mm (or so. Getting an accurate reading within 0.4mm is kinda hard!) I used an accurate ruler, but not a caliper or micrometer. Anyone have experience with this?