torque81

Created a new thread for the issue since I think this may be unrelated to battery replacement as I may not have noticed it earlier. The car in question is a 2016 Lexus RX350 F Sport which I bought used with around 42k miles on the clock. The issue is that sometimes when I am simply standing at the traffic the light with transmission in D, the idle rpm is not constant and it keeps jumping by about 150 rpm or so. Even otherwise the rpm needle is never rock stable as it should be but it could be due to the fact that the rpm instrumentation is fully digital in F Sport and there are 20 notches for every 1000 rpm with each notch corresponding to about 50 rpm and therefore even slight variations will be caught. The question I want to ask my fellow Lexus mates is
1. Is your RX350 idle rock steady? Meaning when the engine is fully warmed up, can you see the rpm needle jump a little however slight (you may really have to look for it).
2. The issue with my car is idle jumping by about 150 rpm standing still and doing nothing. It was reported when my Lexus went in for service for other smaller issues (thread link: https://www.clublexus.com/forums/rx-...placement.html) and while I was able to recreate it whenever I wanted to (gentle stop to complete halt and the rpm needle will fluctuate), I can no longer recreate it. It now happens when it happens. Also attaching the video of the same happening on two separate occasions. I am using premium 98 octane gas. What do you think could be the issue here?
https://photos.app.goo.gl/igQFXMF3yzzUUygXA
https://photos.app.goo.gl/JrHDDvtwmcCTRZBY8
3. What is the technical spec for the idle rpm for this engine if you know? I tried searching but could not find anything. Usually it is specified as xxx +-xx rpm

Thanks a bunch in advance and a very happy new year!

rxtimes2

Both of my RXs are rock steady.

arrowroot

Thanks for sharing the video. My 2016 Rx F sport (Canadian made) does the exact same thing. I had always thought this was abnormal...

torque81

Have you showed it to Lexus? What do they say? I am sending my car in for service tomorrow. Will keep this thread updated with the findings.

DMPesso

my 2017 F sport does this as well, this is normal. Like you said, there are more lines between each RPM so it shows the slightest movement. I wouldn’t worry unless your experiencing other symptoms such as shaking when the idle moves. I’m pretty sure we won’t find an F sport that doesn’t do this. Let’s wait for others to confirm

DMPesso

assuming you don’t have an F sport with digital gauges?

arrowroot

they compared it with another 2016 F sport on the lot and said that they both do the same thing. Their conclusion was that this is normal, based on the fact that both vehicles do this.

torque81

What I am worried about is the 150 rpm jump not the slight jump at idle normally. Does your's do this as well from time to time i.e. like the video's I have shared?

torque81

So your's does the same 150 rpm jump from time to time as in the video's I have shared as well? As per my mechanic, the 150 rpm jump should not happen and therefore he is calling in the car for service. The engine has self cleanup for carbon deposits being a direct injection engine as well but I am not sure whether it is implemented in Lexus or not. It is definitely there in the Tacoma truck with the same engine.

shq

Mine did the same, i now got 2020 f sport and i believe it still does it.

DMPesso

i was looking for someone who got the 2020 f sport and had the older one. Did you get the AVS or standard suspension? Was curious if the new AVS is better then the previous years

shq

I believe fsport comes with avs? Either way i don't feel any difference compared to my 2016.

torque81

Thanks for your response. Do you mean the slight up and down in rpm or the around 150rpm jumps (corresponding to atleast 3 notches on the digital gauge). This idle surge has me worried because my technician is not able to identify why this is happening. There are no error codes either which gets me thinking whether this is a usual behaviour with this engine and therefore asking the fellow owners of the car.

john341

Can you hear the engine revving inconstantly, when the tach is moving like that?

torque81

Yes I can hear it and also feel the vibrations both through the steering wheel and the seat.