P0441 0446 are likely caused by very small leaks at plastic overflow valve on top of the gas tank. The leaks may be so small smoke tests will not find it.

Don't waste time and money replacing parts. You need Lexus diagnostic computer that can turn on and off various components in the evaporative system to find which components are bad. Or find a mechanic with scanning tools that can do that.

I went to Dynamic Auto Services on Harbor Blvd, Fountain Valley, CA. He was a Lexus Master Tech. He charges $90 for diagnostics but will credit it to any repairs made. His work quality is top notch, his rates are very reasonable, turn around is usually quick in a day.