I bought 2 day access for Techinfo (Toyota's official Technical Information System for North America) and downloaded every single file linked to 2016 RX350 and 2022 RX350/L & RX450h/L. Includes repair manuals, wiring diagrams, technical service bulletins, and even some training materials.
DM me if you want it. Not asking for anything just sharing.
In case anybody has the same issue.
This happens every now and then after coming to a stop on a long drive and going to park or neutral. Cleaned throttle body (there's a dedicated video on YouTube for 2016-2022) and MAF sensor then used Techstream to do reset engine values then do idle relearn. Apparently it can be done manually too but I have the software and cable from eBay.
2022 350L. Somehow feels even quieter than the non L ones we have. Same trim levels.