2000 rx 300 wont shift into high gear

It's probably time to have the transmissions inspected. I suspect you might be rebuilding it.

Hopefully it is just a shift solenoid. But be prepared for the worst I would recommend you get it checked by a good independent transmission shop.

That 2000 Lexus RX300 was a great car, but now it is 23 years old. At this point, no modern car with all its technical components is salvageable. You're having transmission troubles because the trans is worn out. You're also seeing minor things like wheel sensors, engine sensors, and electrical issues. The car's worth around three grand and the transmission will likely cost near that..... Time to kiss that beauty good-bye and go shopping. Just be thankful for all the years you had with her.