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I’m having this exact noise issue. It’s like a very low rumble and goes away when pressing the gas. Cant hear it outside of the car. 2014 with 160k miles
I’m having this exact noise issue. It’s like a very low rumble and goes away when pressing the gas. Cant hear it outside of the car. 2014 with 160k miles
Yes exactly, the same issue as we are having. Mines a 15 with 115k and started doing this around 105k. It's very intermittent with no pattern so it's kinda hard to diagnose with little information. It doesn't seem to effect any operations of the vehicle but like you said, when you give the throttle pedal just a slight rev it goes away but then comes back immediately when the idle drops back down. Another member mentioned it could be the vacuum pump, which makes some sense in the fact that mechanically it sounds like it fits what's happening. But to replace the vacuum pump with how much it costs just to see if the noise goes away seems uneconomical as I'm not experiencing any negative functionality from the noise, just some annoyance. I just made a comment back on this thread to bump it to the top again to get some fresh eyes and any new ideas on the table.
Yes exactly, the same issue as we are having. Mines a 15 with 115k and started doing this around 105k. It's very intermittent with no pattern so it's kinda hard to diagnose with little information. It doesn't seem to effect any operations of the vehicle but like you said, when you give the throttle pedal just a slight rev it goes away but then comes back immediately when the idle drops back down. Another member mentioned it could be the vacuum pump, which makes some sense in the fact that mechanically it sounds like it fits what's happening. But to replace the vacuum pump with how much it costs just to see if the noise goes away seems uneconomical as I'm not experiencing any negative functionality from the noise, just some annoyance. I just made a comment back on this thread to bump it to the top again to get some fresh eyes and any new ideas on the table.
In 2016, I took my 4GS to Lexus while still under warranty.
Lexus said that the intermittent rough idling was due to a dirty air mass sensor.
Lexus cleaned the dirty mass sensor for free, and I have had smooth idling ever since.
I'm not sure how the air mass sensor ever became dirty.
@peteharvey just curious before they cleaned the sensor, did you notice the problem go away with light throttle while in park (almost as if the idle was too low and bringing it up slightly removed the dull sound in the cabin)? I'm also experiencing a similar issue as a few others here but it doesn't seem to throw any codes or cause any other problems...
@peteharvey just curious before they cleaned the sensor, did you notice the problem go away with light throttle while in park (almost as if the idle was too low and bringing it up slightly removed the dull sound in the cabin)? I'm also experiencing a similar issue as a few others here but it doesn't seem to throw any codes or cause any other problems...
Yes, I remember something like that.
Back in the 1980's, I would use a screwdriver to raise the idle speed for my Mazda 323 1.5 and 929 2.0 single carbies, but nowadays, due to electronic fuel injection, I cannot raise the idle speed myself.
However, fortunately it was the dirty air mass sensor, because I'm not really keen on raising the idle speed, since that would cause higher idling noise and higher fuel consumption.
Last edited by peteharvey; Feb 17, 2024 at 05:18 PM.
@peteharvey just curious before they cleaned the sensor, did you notice the problem go away with light throttle while in park (almost as if the idle was too low and bringing it up slightly removed the dull sound in the cabin)? I'm also experiencing a similar issue as a few others here but it doesn't seem to throw any codes or cause any other problems...
Yes, with light throttle the sound immediately stops. But then immediately comes back when you let off and the idle comes back down. Someone had mentioned that it could be the vacuum pump which is a possibility. I'm going to get my $500 Autel scanner hooked up to my car and see if the vacuum pump turns on when the sound is active to see if it is correlated. Just looking at my long term/ short term fuel trims I might have a vacuum leak on bank 2 of my engine.
2015 GS F Sport, 148k, adult driven … had since 30k as a lease turn in, bought from dealer.
I have this same elusive noise. So frustrating to my OCD. I’ve actually lifted the car on all four corners, went from front to back, top to bottom looking for any vibration from heat shields to exhaust.. no results.
I turn my own wrenches so I am very familiar with the engine bay and nothing seems out of place. I’ve replaced the main belt pulley thinking that the bearing was out. Result- I now have a back up to the new one when that goes/ if it does.
I hesitate to take it to the dealership because it never fails something always goes wrong with some other non-related item after I get it back. ( they did a coolant flush and charged me full service but only used one gallon of new coolant - nutshell- the tech did Not drain the two engine peacocks and left two gallons of old coolant in my system. )
anyways, not trying to vent too much but just glad I’m not the only one with this mysterious friend of ghostly noise.
I do hope we get an answer soon because I don’t like ignoring something that apparently has changed from factory.
sorry for the long read but I’m venting.
Last edited by NewGuy109; Mar 26, 2024 at 03:49 PM.
Yes, with light throttle the sound immediately stops. But then immediately comes back when you let off and the idle comes back down. Someone had mentioned that it could be the vacuum pump which is a possibility. I'm going to get my $500 Autel scanner hooked up to my car and see if the vacuum pump turns on when the sound is active to see if it is correlated. Just looking at my long term/ short term fuel trims I might have a vacuum leak on bank 2 of my engine.
@GSJ350 just curious if you ever found any leads with the vacuum pump or anything fuel related to this noise? Peteharvey mentioned Lexus cleaning a dirty mass air flow sensor did the trick for him...
Originally Posted by NewGuy109
2015 GS F Sport, 148k, adult driven … had since 30k as a lease turn in, bought from dealer.
I have this same elusive noise. So frustrating to my OCD. I’ve actually lifted the car on all four corners, went from front to back, too to bottom looking for any vibration from heat shields to exhaust.. no results.
I turn my own wrenches so I am very familiar with the engine bay and nothing seems out of place. I’ve replaced the main belt pulley thinking that the bearing was out. Result- I now have a back up to the new one when that goes/ if it does.
I hesitate to take it to the dealership because it never fails something always goes wrong with some other non-related item after I get it back. ( they did a coolant flush and charged me full service but only used one gallon of new coolant - nutshell- the tech did Not drain the two engine peacocks and left two gallons of old coolant in my system. )
anyways, not trying to vent too much but just glad I’m not the only one with this mysterious friend of ghostly noise.
I do hope we get an answer soon because I don’t like ignoring something that apparently has changed from factory.
sorry for the long read but I’m venting.
@NewGuy109 agreed its a very annoying sound - makes the car feel less "luxurious" IMHO.
Electric motor of some sort running under trunk area
Good morning,
this morning when I went into my garage, I heard a humming sound (possibly a small electric motor of some sort ) coming from under the rear of my car. From underneath the trunk area.
Note - my car had been off for well over 8 hours so this is a concern as I don’t want a battery drain.
Anyone know what motors are up inside the black plastic under plate, under the trunk?
Thanks again.
Or it might be the EGR value whistling as the pump purges pressure from the canister.
The last car I'm aware of with that same noise exploded and destroyed 47 other vehicles including a Greyhound bus!
Just kidding!
Well THAT would probably help STOP the noise! lol but in all seriousness, this mysterious elusive off/on muffled noise plays games as I idle at EVERY stop light!!!
Many threads have mentioned a " refresh", im not sure if that would help this but I will call the dealer and ask. Until then I will just keeping checking back to this string of knowledge looking for our collective answer!
Lexus dont fail me now! I want another 1
50K out of ya! lol
I am experiencing a similar annoyance with my 2015 GS350 F-Sport RWD. I was able to capture it on video. Vacuum pump (from what I can find online, only 2016+ has a vacuum pump)? I’m hoping someone has found the remedy by now.
The rumble noise goes away with a little throttle input, then immediately comes back when the RPMs drop. I’d love to get this addressed before my CPO warranty expires.
I am experiencing a similar annoyance with my 2015 GS350 F-Sport RWD. I was able to capture it on video. Vacuum pump (from what I can find online, only 2016+ has a vacuum pump)? I’m hoping someone has found the remedy by now.
The rumble noise goes away with a little throttle input, then immediately comes back when the RPMs drop. I’d love to get this addressed before my CPO warranty expires.
I posted a video a couple weeks ago or so about the different sound it makes for the first 22 seconds or so after it is started. It only happens when I first start the car after it is completely cold. I was told this is normal, which it might be because I don't hear it unless the car is cold. I don't hear this after it initially starts at all, but does this sound match what you guys are all hearing? https://share.icloud.com/photos/0e6l...gmZlr6v8jysrHQ
Mine has also been making quite some noise upon cold start. I noticed if I park it outside overnight compared to the inside the garage, the start up is much louder. It sounds like hissing/ air escaping for the first 5 mins of starting. Another sound that im sure is related is alternator whine when accelerating. Upon startup and in idle it's at its loudest, once I change to drive or reverse it isn't as loud but it has this whine sound. And after about 5-10 minutes of driving the noise is gone with still minimal whine. If it's any possible factor, I did have the short engine block replaced a few months ago. I also did have the idler pulley belt and spark plugs replaced last week but the sound is still there. Attached is link for two videos of start up and idling. TIA for anyones advice on this.
I posted a video a couple weeks ago or so about the different sound it makes for the first 22 seconds or so after it is started. It only happens when I first start the car after it is completely cold. I was told this is normal, which it might be because I don't hear it unless the car is cold. I don't hear this after it initially starts at all, but does this sound match what you guys are all hearing? https://share.icloud.com/photos/0e6l...gmZlr6v8jysrHQ
Originally Posted by shadowx055
Mine has also been making quite some noise upon cold start. I noticed if I park it outside overnight compared to the inside the garage, the start up is much louder. It sounds like hissing/ air escaping for the first 5 mins of starting. Another sound that im sure is related is alternator whine when accelerating. Upon startup and in idle it's at its loudest, once I change to drive or reverse it isn't as loud but it has this whine sound. And after about 5-10 minutes of driving the noise is gone with still minimal whine. If it's any possible factor, I did have the short engine block replaced a few months ago. I also did have the idler pulley belt and spark plugs replaced last week but the sound is still there. Attached is link for two videos of start up and idling. TIA for anyones advice on this.
