I think yours sounds pretty normal just deeper which actually sounds nice. Mine feels like it’s a rustling and scratching.

 

At the very end of the video, he says something that could be a lot worse with Lexus 3.5 engines. It seems like it is quite a bit different than the first 5 minutes of the video, but nevertheless it is definitely a really interesting video and good to be aware of, thanks for sharing!

 

I have had this SAME rumble noise randomly at idle when car is warm for a few years on my 2015 IS350. Comes and goes at idle and goes away as RPM increase (thank god).

Was never able to figure out what is was.

 

This is good information as it is not specific to the GS. This morning the rumble came back while the car was in park, and stopped after I pumped the brakes a few times. Not sure if that was just a coincidence. Also, the noise is intermittently present when the car is cold. Here’s another video showing how the noise changes slightly with the RPM before it goes away completely.


This time, pumping the brakes had no effect.

 

Hey This is exactly the noise! Unfortunately I tried to have it checked out but no one could find anything(almost impossible to replicate it as it just comes on randomly and random times). I have to get some work done on the car this year so i will probably take it to my trusted mechanic to have a look over. My car now has 208,000 kms from when I last posted so clearly its not a major issue.

 

Mine has been at the dealer for a week. They have reproduced the sound multiple times but have not been able to figure out what is causing it. On a positive note, the 2023 RC350 Fsport they gave me as a loaner makes me like my vintage GS350 even more.

 

I doubt you'll ever be able to get rid of that sound the car makes, nor the slight rpm change it make at idle from time-to-time. The engine ECU controls all parameters of engine performance from ignition timing to air and fuel delivery, and everything in between. A slight change signaled from an oxygen sensor, a coolant temperature sensor or an oil pressure sensor is all it takes for the engine's ECU to adjust to those signal inputs. Those parameters are constantly changing and no one piece of it that is part of the whole can be isolated or singled out because all those various factors of the whole defines how the engine management system operates. It would be like trying to determine and also trying to isolate and control a human's emotions as it relates to the subject's heart rate and heart pressure. It just can't be done unless the human is put into a therapeutic coma for extensive deep-dive analysis. That cannot be done for a automobile... I recommend just accepting it as typical and normal.

 

Well the RPM fluctuation is me pressing on the gas pedal to make the annoying rattle go away, which lowers my heart rate and puts me into a therapeutic coma of sorts.

There is a TSB for a fuel line contacting and vibrating against the frame on some 2016+ GS350s, I wonder if we could be experiencing something similar.

 

So, what was the outcome of looking into the FUEL LINE RATTLE/KNOCKING NOISE TSB on your car? Find anything?

 

He, my gs350 2014 with 105k miles start making this strange pumping noise just a week ago. Mostly happened every morning after 5-10 min drive. Than goes away until next morning. I did check fuel lines but they are secure

 

Kind of an oddball suggestion, but see if there is noise coming from your air conditioning blower located on the passenger side of the dash. I have a Toyota Sienna that went through OEM blowers like nobody's business. I ended up swapping the bushings out with bearings to get rid of it. It didn't sound like the blower was going out... it sounded like there was a mechanical engine problem. The squirrel cage for the GS blower looks smaller and the dashboard is better insulated for noise. It might be worth just checking it out and it is easy to do. When you hear the noise just turn your AC system off. If the noise persists then it's something else.

 

What i found is fuel line has vibration next to the fuel tank. But it happens randomly. Overseas forums complaining about fuel pump causing issues. Waiting for a new fuel pump assembly to see if that helps

 

This really sounds like what I’m hearing. I was hoping to crawl under there this weekend but a deer had different plans for my car. Guess my problem is fixed!

 

sorry for your loss. New fuel pump does not change anything. Was able to track issue. Noise coming from port njection fuel rail. That rail comes with two pulse regulators. Probably one of them bad.

 

Did you ever fix the problem? If so I wouldn't mind hearing what you did.