I just bought a 1999 RX300 with 30,000 actual miles on it. Garage kept in and dealer service.
I want to know what maintenance should be done right away. Thank You, LexRX99

 

Do you have the service history? If not go to lexus.com and enter your VIN. But easy to answer replace all fluids.

 

At this time think you are 0 miles and replace all fluids.
Check dates on tires and most likely you would need to replace them.
Have the battery test with load [be prepared to replace it]
Treat the leather.
Cycle up the A/C.
Read the Warranty and service manual and start follow the service intervals,

I am happy that you found a low milage RX but at the same time a machine that is not used does not mean new. Plastic is all hardened. Leather and rubber and foam has lost its flexibility. Dry rot may be present. Bushings/suspension may not be pliable.

I would gradually bring the vehicle to new normal.

Congratulations and welcome to ClubLEXUS.

Salim