After searching a lot here, the ES300 V6 engine problem of consuming oil and starting smoke are very common. Lack of maintainance and sludge are the culprit.
LEXTEK1 explained really well.
https://www.clublexus.com/forums/es3...uming-oil.html

My 98 is one of them, I don't have the garage, take the engine apart to clean the sludge that is not possible in public parking lot.
It is not the total solution. The best way is to open the engine and clean the sludge directly.
Here is a micky mouse method hope may ease your pain.

It is an add-on system, totally reversible in 10mins.

Version 2 - Modifiy the oil catcher can to oil reservoir.
1. Drill the back original PCV to make it open. Air and oil can go in and out freely from engine.
2. Tap a new hole at the lowest point of can and connect to modified PCV to engine.
3. Put a new PCV at the highest point of the tank. It serves as stock function.

How it works?
When the engine is running, especially when running up the hill. The sludge engine will pump out a lot the engine oil to PCV!!!
Now, the modified oil reservoir will collect the oil and let the air go through the new PCV.
And the most important thing is the oil will return to the engine when shut off.
Reduce the consuming oil, less oil escape from new PCV, less oil go back to the intake, less starting smoke is the result.
It does reduce the losing oil rate ~95%, no more embarrassing smoke when start the engine.
No more magic dragon "Puff the smoking engine, la la .......bye bye."

The catch cans are a violation of the Federal Emissions law. Modify your car at your own risk.

https://www.youtube.com/watch?v=AF7zTK8x1Q4
After 70km trip up and down the hill, it catched ~80ml oil inside the tank already.
When shut off the power, oil return to the engine immediately.