Hi All,

After the engine is warmed, my normal idle in drive, park, neutral, or reverse is around 650-700 RPMs.

I have recently noticed that when a combination of conditions occur, my idle hovers around 450-500 RPMs and is pretty rough. This low, rough idle occurs when:

1) The car is in drive;
2) The car is at a full stop (foot on the brake or auto-brake hold);
3) All accessories are off (heated seats are off, radio is off, headlights are off); and
4) HVAC is Off.

I went to the dealer and they ran diagnostics. No error codes were recorded. The dealer looked at other ls460s and said they all do that.

Does your LS do that too? Would love to hear your input!

By the way, I noticed this after my VSR was done.

 

I have an 07 and had the VSR done, I dont experience any of this, mine idles actually better than it did before VSR. It is usually in the 500-700 range

 

May want to have your dealer check for this L-SB-0033-08

 

Mine (2007) does the exact same thing. Have a friend with a 2008 and it does it also. Hard to believe this is "normal". I have owned 430's and 400's and they all idled very smoothly. I am going to take mine to a local lexus mechanic.

 

had the same thing done and it helped but I have been noticing it doing it again just not as bad. With he AC on its fine but without it it idles slightly ruff. I remember having the same issue with my G35 and they simply added 100 rpm to the idle through the ECU. The people at my old dealership said it couldnt be done

 

so what was the resolution? did the dealer fix it ?

 

This is a 3 year old thread, and the op hasn't posted since the original date. If you are having similar issues, you should start a new thread.

 

Not an LS, but an ISF. After the car is warmed up there will be times when at a stop light the idle will hover ~500rpms. As a result, there is a bit of a "rough" idle feel, at least for a Lexus. However, this appears to be a well-documented non-issue on the ISFs, so aside from just noticing it there isn't much to do.

 

I have an 07 with the exact same problem. The Lexus dealer says it is normal - I also had LS 400 and 430's which did not do this. My Lexus dealer says it is because Lexus changed the 460 to a timing chain (the others had timing belts). He said a timing chain will never be as smooth as a timing belt. I also took my car to my local independent Lexus mechanic and he checked it out and said there was nothing wrong that was causing it - it was due to engine design. So I have lived with this for years. When I come to a light and stop and it does it, I put it in neutral which raises the rpm to ~700 and smooths out the idle some. My 2 sons have 8 year old Camry's with 4 cyl with 150k miles that idle smoother. It is unfortunate that Lexus has ended up with their $80k flagship car doing this (along with the infamous wind noise issues).

 

My '07 also had somewhat of a "rough" idle with the a/c off. I noticed it when I bought this car from my mother in late December, 2013. Figuring there would be no harm, I tried some Techron fuel tank additive along with several full throttle pulls in 3rd, 4th and 5th gears. Somehow, it worked. For the last 3 months, this car, now at 47,000 miles, idles so smooth at 500rpm (a/c off) it's unbelievable. 700 rpm idle (a/c on) is just as smooth. I'm not normally a believer in automotive aftermarket additives and will concede that my result may be coincidence. This car has had the fuel rail and valve spring recalls done.

Many members here know that the fuel injection and its management is fairly complex on LS 460's. Which injectors are used and when is really interesting. Here is a brief, simplified version of what's going on.

Cold start: Both port and direct injectors, Direct injection on compression stroke

Warm-up idle: Port injectors only

Normal idle: Direct injectors only, injects on intake stroke

Part throttle (cruise): Both port and direct

Full throttle: Direct injectors only, injects on intake stroke

 

Well, problem is my LS460 is shaking during idle.. I mean shaking, make me feel dizzy. its fine while the wheels are moving though, shaking in both Park and Drive (at stop sign/red light). got check engine light with cylinder misfire. Did have the rocker arm recall/service back in 2011... dont know what's going on

 

Bad spark plug?