low idle around 400 rpms
This generation of Lexus GS models has a known issue for this and can often be corrected by cleaning the throttle body (https://www.yourmechanic.com/services/clean-throttle-body). I would also recommend testing the MAF (Mass Air Flow sensor (https://www.yourmechanic.com/services/mass-airflow-sensor-replacement)) as well as this can...