Pilot

Since MMO is cleaning varnish out of the engine. It is recommended that you start with clean oil and a new filter, then add the one quart of MMO with your normal oil. I would run it 1000 miles, then change oil and filter back to what you normally want to use. I would not recommend over filling your oil now, or adding a quart of MMO later during the last part of your mileage before an oil change, like at the 2000 mile mark of a scheduled 3000 mile change. You can use some cheap Wal Mart oil and filter for the 1000 miles, so you can do the MMO treatment for under 20.00.
The Lexus engines are tough, but they have no defense from varnish that builds up over time and mileage. It would not be the engines fault if the valve lifters get slightly gummed up or piston rings get carbon and varnish behind them, which can cause oil burning and smoking. I don't like to use harsh cleaners with high a concentrate of solvents etc, which are available. The MMO is an oil base cleaner with mild solvents, and which enjoys a long history of working wonders in all engine types, and will never harm an engine. It will not clean out all the varnish, with just one use, so this is why I generally use it one time per year for the 1000 miles. I use it in the fuel about every other month, at 1 oz per gallon of fuel. It would not hurt a thing if you just used a full quart with a full tank of gas.
Marvel Mystery Oil has been used in aircraft engines since back in WWll, in the 1940's the military bought it in 55 gallon barrels. They used it in the oil and the fuel of radial aircraft engines. I talked to a aircraft mechanic recently who told of a recent small aircraft engine he overhauled. It looked new on the insides, but was due for an overhaul for the all the hours it had flown. He asked the owner about the clean engine, and was told by the owner how he had always used Marvel Mystery Oil in the fuel and the oil. The mechanic said it was the cleanest engine he had ever seen!

Pilot

spxChrome

I talked to a friend today about it and he also uses it. He said to add it to the oil about 500 miles before the change. After running it for 500 miles then change the oil and you are all set.

What do you think about that?

Pilot

Well, everyone has thier own opinion on how to use MMO. The above mentioned plan should still work, but I will stick by my own method of starting with clean oil. Some folks run it 500 miles like your friend, and others like me run it longer if the engine has lots of miles on it etc. One way or the other, you are not going to hurt anything. Go ahead and run it in the fuel for a full tank too.

Pilot

SCV8

I used to have a valve that stuck a little,I just used hevron/Texaco gas for a year or so and it gradually went away.Marvel oil is good too.
The noise might be your injectors,if it's a constant one,the valve sticking will come and go.