My 2000 RX300 with 208,000 miles to be pinging even under reasonably light loads. Not normal. It did not use to do that. Is the engine too worn out.

What should I check / fix?

Is there a reliable supplier of an engine with low miles? I read somewhere that JDM (Japan Domestic Market) engines are incompatible with a US delivered vehicle

 

Replace engine ?!?! I think I would replace the knock sensors first, or have a good shop diagnose what is going on.

 

Yeah, "replace engine" shouldn't be on your list of "steps to resolve engine knock".

 

Are you running 91 octane and like the guys said above check the knock sensors. Do you do a lot of short drives from here to there.
My 2001 RX300 has 202,000 and no problems but years back I ran 87 octane and I sure from the engine lots of pinging. Once I went back to
91 octane no more problems I also take my RX300 out on the open highway/freeway for at least 10 to 15 miles to clean out the engine.
I also use Lucas Injector cleaner every other fill up buy it by the gallon at Walmart. All I use is Arco/Costco gas

 

Yes. Replace engine is the last resort.

The Knock sensors are brand new Toyota.

 

I would put off the engine replacement, unless the problem can not be cured easily and the rest of the vehicle is in a state that it should not be put out in the pasture [crusher]. If you are a hobbiest and need a project car then spending-vs-fun is at your discretion.

Check out compression of each cylinder and also do a leak down test.
Examine for carbon buildup and see what can be done to remedy it.

Remember nothing lasts for ever. At the same time I am not suggesting a premature junking.

Salim

 

@salimshah - you caught me. I always need a project car.

My RX300 is mint otherwise. And for the longest time, I promised myself that if the engine goes bad, I will replace the engine. This RX300 made me a believer in Lexus. I used to wonder that nothing ever seems to go wrong with the vehicle. Bullet proof.

My driveway looks like a Lexus dealership now. Kids grew up and got their license. So I got them both a Lexus RX350. And I am in the lookout for a 3rd one since the wife wants one too. So if anybody has an RX350 to sell, let me know.

Getting old now. Body is not flexible enough for wrenching and going underneath cars. Time is coming for me to get rid of my hobby cars. So the BMW and Mercedes are on sale. Next hobby will be Electronics repair and troubleshooting. Maybe repairing ECU's or Electric Vehicle power regulators...

FInal question - any tips on how to find a local specialized Toyota mechanic who can diagnose this issue I am having?

 

IMHO any shop should be able to perform the tests I listed.

Check for non European Import specialists if you can find specifically Toyota mechanic. There is a good chance that they have worked on a Toyota.

Salim

 

Did the pinging start after you installed the new knock sensors?

 

No. The pinging was going on before Knock Sensor replacement. I had to replace Knock sensor because the car was already hacked for Knock sensor. WIth the second knock sensor failing, the vehicle was in limp mode.
Even with new Knock sensors, I was getting the Knock Sensor DTC. So I reverted back to the hack where one Knock sensor feeds the signal for both banks. That fixed the code.