jrmckinley

2010 460L, 103K miles. Have owned a 1996 LS400 and 2004 LS430 prior to this. I've always noticed that I hear the engine slightly more at idle (in "Drive") in the 460 but I've gotten used to it. However in the last few months, I feel I'm starting to notice the difference in sound at idle a bit more than in the past and I feel a very slight vibration. If I put the car into "neutral" it's basically silent and completely still like the 400 or 430 were in "drive". But once in "drive" I just hear a slightly deeper sound. AC is on, etc. I've read the forum posts about idle but those seem to be talking about the RPM's not being where they should be (mine are at exactly 700 or 800 in "Drive" which is where the ECU wants it).

So what are some things that can lead to this subtle change in the amount of noise I hear at idle? Throttle body needs to be cleaned/replaced? It doesn't really bother me, but I am noticing it and just curious what the potential things could be that contribute to it so I can keep an eye on it and inform my mechanic.

Thanks,

unabee

I don't think you're talking about a "rough idle", that would mean the engine is running uneven or misfiring or some other performance issue (you'd probably have a CEL in a modern car).

My guess is you're describing what we all feel after a few years, Broken or worn out motor mounts.

Im still trying to get the motivation to do mine, but they're a bit involved to replace.
Currently, this is the best method for a DIY'er :
https://www.clublexus.com/forums/ls-...l#post10677082

Many shops will shy away from the job, or charge you a mint for the job (OEM Parts are $300-500 depending on where you buy them for all three mounts, labor is ...more). If you find a better way, please let us know.

jmcraney

The question is: is your car making more noise, or are you hearing more noise? Several people have told us that an application of silicone grease to the door and window seals enhances the isolation of the cabin from outside noise.

miket000

I went through the exact same scenario with the noise / vibration at idle. It is your engine mounts. Before I changed my mounts I did a very thorough tune up, you name it I probably did it. Only the 3 new mounts stopped the vibrations. I do agree at first I thought it was a tune up issue or worse. The mounts really do an amazing job at isolating the engine. That is probably why they are aptly named isolation mounts

jrmckinley

Are these able to be checked by visual inspection to see if they are bad and the source of my problem?

johnnyg66

Somewhat. You can get under the car and do a visual on them. If you have someone rev the engine on and off and you watch the motor movement. If you see too much play than good chance your mounts are bad. The transmission is a bit tougher but since they are easier to change and one can do themself i would try that first. The engine mounts are a whole lot harder to swap.

jrmckinley

OK thanks. I think what's confusing is the only time I hear or feel anything is when I'm completely stopped in "D". The second that I start moving and the RPM's are slightly higher, there is no noise or vibration. And there is no noise or vibration in neutral at all.

sha4000

iTrader: (1)

If you put the car in neutral/park while at idle do you still feel the vibration? If it goes away then this would point towards engine mounts since the engine would be disconnected from the transmission in those scenarios.

jrmckinley

No noise or vibration in neutral or park. What you're saying makes sense! Thanks

miket000

The lexus dealer did a visual inspection of our mounts. They did not find any problems with them. Replacing the mounts will resolve your vibration issues while stopped in D.

jrmckinley

Good stuff, thank you. Any ballpark of what this costs for those of us who are not DIY?

UDel

It can be any number of things

Dirty Throttle Body
Dirty Spark Plugs
Dirty/clogged Fuel injectors
Low RPM for whatever reason
Bad Motor mounts
Engine issue, stuck lifter.
Just to name a few. I would try a fuel injector cleaner like Redline. Check and wipe down the tips of your spark plugs or replace them if they look bad, clean your throttle body.

Nospinzone

Agree, this is good advice.

I learned this lesson the hard (read: expensive) way about 40 years ago.

fooldall1

Could also be a faulty or failing Cam position sensor (or wiring to them, the clips can be flimsy and easy to damage when removing coil connectors) I noticed it for MONTHS before a CEL forced me to dig in there and test the sensors and conectors. I had to splice two new pigtails on the Bank 2 sensor circuits. The center RED cable pulled easily out of the Bank 2, Sensor B vvt/exhaust side. also had to replace the camshaft position sensor due to the same reason- wire eaily slid out of the connector terminals. After that, smooth again like new in drive, park, with or without AC on, in park, Drive, etc.. Makes sense, too- the functioning of those sensors determines the timing advancement of the cams (or retardation) and "clack" a lot when not functioning as they should. after the work was said and done it made a HUGE difference in the overall "Diesel like" sound that the engine made before the change, now, all I hear is the fuel rail click as usual. I imagine the spec of the CEL is above the point at which it starts to make some racket.

For the record, it eventually threw a P0340 and P0390 codes.