what should it be for example at at stop light with no a/c, lights or accessories on?

 

What are you seeing?

 

 

If you are saying 620 is best does that mean that 600 is bad?
that is what I have and it shakes
does yours?

 

Your car should not shake, you'll hear the "firing" of the injectors and other noises, but very limited to no engine shake. Basically, you'll want to see between 600-650rpm since the needle doesn't give us a digital read out.

 

EDIT: Oops, I was thinking about my RX300 and forgot I was on the ES350 forum. Apologies, but maybe the info helps. BTW, I do not have noticeable idle vibration with my ES350.

Plenty of RX300 owners complain about noticeable vibration at idle when the car warms up. It definitely gets worse as the RPMs drop, especially at sub 700. Mine idles at 620 when fully warm. I would prefer a higher idle as it would greatly lessen the vibrations. Often at traffic lights I slip into neutral, as that raises the idle RPM and improves the vibration.

A number of RX300 threads discuss this, starting many years ago. Some people changed out engine mounts and often found no noticeable improvement. But a few have said new engine mounts did improve things.

Here is a thread from 2006
https://www.clublexus.com/forums/rx-...e-problem.html

Here is another more recent one
https://www.clublexus.com/forums/rx-...ion-issue.html

 

 

I understand this to be the normal range regardless if all accessories are on or not. The IAC should control variations due to load o the engine.

 

well one thing i know foe certain is the rpm goes up when i turn on the a/c
re Lexmus: how do you raise idle rpm on this car?
it is all fly by wire, no?

is low (600) rpm at idle a sign of a problem and if so, what can be causing this?
i understand that vibration can be caused by a million things from a simple mount to a compression issue but vibrations aside what is the reason for low rpm in gear at idle?

 

Do some info look up on the IAC and throttle body function and you can understand how the idle system works . These functions are programmed into the ECM . The engine load is compensated for and the IAC is adjusted to the programmed parameters. If you have deviations with load idle or base idle there is a problem with a component. It may be a dirty throttle body or a sticking IAC. Before I would get into those areas I would look at the simple things like changing the air cleaner.

 

thanks
air filter had been changed and throttle body has been cleaned by lexus dealer 5000 miles ago
so this leaves the iac valve?
how do i service this?

 

There is no IAC on the ES350. What's the mileage on the OP's car?

 

 

The idle air control unit is built into the throttle body. If you remove the black plastic case on the throttle body you will see the functioning plunger.

 

If you check out the correct engine model (the 2GR-FE) and the associated TB info you will see that there is no IAC valve (intregral or otherwise). If you look into the TB bore (before and after the throttle plate) there is no throttle plate air bypass passage that you would see if there was an integral IAC valve.