One problem related to catalytic convertor has been reported for the 2000 Lexus RX300. The most recently reported issues are listed below.
After approximately 62,000 engine light illuminated. The oxygen sensor was replaced by my local repair shop. After the engine light came back on, and I reattempted to use my local shop 3 times I brought it to the dealer. The problem is the mass airflow sensor/meter. This seems very premature for this type of part to fail. For a auto comapny that professes quality I was disappointed for this problem to arise. I am past warranty and am petitioning Lexus to pay for some of the repair.