[QUOTE=peteharvey;11459894]The bigger the engine capacity, the greater the reciprocating mass.
Hence, of the V6's, the 2.5 is naturally smoothest, then the 3.0, while my 3.5 starts to get a bit rough at idle and full throttle.
In truth, the 1.5 and 2.0 V6's are smoothest, but little torque - unless turbocharged.While 3.7 and 3.8 V6's in Maxima and Hyundai/Genesis are naturally rough, especially at full throttle.

I find that the longitudinally mounted 3.5 in GS has a rougher idle than the transversely mounted 3.5 in the ES.Also, the exact same make and model, even when brand new, I find that some are naturally slightly rougher than others!
For example, I purchased my GS350 brand new, and it always get Toyota 0 W20 fully synthetic oil, but I find that it is always slightly rougher revving than other brand new GS350's.

One final factor, especially if the vibration is at idle - when brand new, my 3.5 used to intermittently have a terribly rough idle in the colder months, Lexus cleaned the air mass sensor under warranty, and the idle has never been so bad in the colder months again; however, I must say that even under normal conditions, the 3.5 doesn't idle as smoothly as my 3.0, let alone my 2.5.
Hence, ask them to clean your air mass sensor with a spray can. Hopefully that helps. ​​​

Well I will have the check the air sensor, but, while you're no doubt technically correct about reciprocating mass and all, meaning no offense, I don't buy that as a reason. I have owned two previous V6 ES's and never experienced a vibration imposed into the steering wheel, The same goes for numerous V8's which were buttery smooth at idle. Either the damping system such as the mounts are faulty or there is something other than design that is the problem. Hopefully they can figure it out.

 

I bet it is the air mass sensor?
That's what happened with my 3.5.
It was such an intermittent nasty idle in the colder months.
In the warmer months, it would disappear.
The vibration was extremely severe, and the whole dashboard used to rattle.
Lexus fixed all under warranty; cost me nothing.

Why Is My Car Idling Rough? | The Family Handyman
Symptoms of a Bad Mass Air Flow Sensor - In The Garage with CarParts.com
8 Symptoms Of A Bad MAF Sensor [& Replacement Cost] (mechanicbase.com)

Despite fixing the air mass sensor, my 3.5 still does not naturally idle as smoothly as my Lexus 3.0 and 2.5 V6's, but that is unavoidable; we cannot cheat physics.
However, around town, my 3.5 is "perilously smooth" and it purrs like a cat - unlike my wife's IS200t which is very "throbby" around town when off-boost.
On full throttle, my 3.5 is a trifle harsh - though I'm very picky when it comes to refinement.
On full throttle, my wife's 2.0 Turbo surprizingly revs more smoothly despite having only 4-cylinders and a narrow bore with long stroke - a bit of a surprize; however, I find that Benz and BMW 2.0 turbos rev much more smoothly, both at part throttle off-boost and full throttle.

 

My IS350 F Sport only a couple days old is very smooth at idle and I assume the same engine

My ES is a hybrid.

 

Same issue in my 2021 ES 350 UL, excessive engine vibration while idling among other little issues. I wasn't expecting it from Lexus, not in a car labeled as luxury, definitively not ultra luxury. In general I'm disappointed with Lexus build quality. It appears legendary Lexus quality is a thing of the past or maybe it applies to models built in Japan.

 

Did you ask the dealer about? Mine couldn’t help me.

 

Not yet but I'm taking it in again on Monday for rattle which sounds like it's from panoramic moonroof and brakes chatter so will mention engine vibration as well.
Will see. I doubt they will do anything to fix vibration. It's a good-looking car, though, too bad it is not as good mechanically ... or maybe it's my luck.

 

Mine seems pretty bulletbproof so far mechanically and thats after five years and nearly 70k miles. Vibration - none. Panoroof I wouldn't touch with a long pole. OEM brakes I agree aren't great. Had mine refreshed at around 40 or 45k - had to have them redone shortly thereafter on the inde shop's dime as Im guessing they used crappy parts from China. They're perfect now. Hope the dealer can resolve some of your troubles.

 

Panoroof looks so good in this car, though. I just couldn't skip it in fully loaded UL but wish I researched it bit more before ordering the car.

What rotors and pads did you use to make brakes perfect? I may have to do the same myself even though the car is still under warranty. Dealer has already replaced all rotors but chatter came back after few hundred miles. I agree, probably some cheap warped rotors. I would never expect it from Lexus.

 

I didn't do the work myself so really don't know but I politely asked them to use top quality parts - they smiled and said this won't happen again. The brakes now really feel better than when the car was brand new.

 

I bought larger front rotors and calipers made for a 2011 Toyota Highlander, and Akebono brake pads. They bolt up to the hubs on 6th gen ES with no issue. Did Akebono pads on the rears with ES rotors. Brake performance is superbly better.