skyzhuang

Just found this situation today... Just like video shows. The idle is normal when it is in P or N, and it runs with no problem once I accelerate. Did anyone also meet this situation?

skyzhuang

And the engine starts vibrating, shaking when the idle is pretty low... It feels like it's gonna be turned off. I put a bottle of fuel injection cleaner in this tank of gas, so it shouldn't be the problem of fuel injector. And the engine runs smoothly during driving.

swfla

iTrader: (1)

Year and miles?

skyzhuang

2013, 116435 miles

Gerf

Hey Sky, ya wad you gat there is some warn out cantrol arm bushings...see what happens is when drivin they start knokin and shaken making a harrmonick residence and this cozes the knack sensore to retahd the timing and lows the idel speed.
Betta get em fixed fast before it takes the hole reer end out.

XF40FSPORT

Is it already 5pm in your neck of the woods??

BB9

If check engine light is not on it sounds very much like your fuel system needs some cleaning. With that said, dumping one bottle of cleaner at this mileage is not going to do you any good, it takes time to dissolve all the deposits in the throttle body and the injectors. I had this scenario with ES350 when I bought it several years ago (it was 50K or so used car) It took several fuel tanks with appropriate cleaner to fix the issue. Besides, you have to remember that LS460 has 22 gallon tank and most of the cleaners made for smaller quantities of fuel. I'm using two bottles of Chevron Techron (one bottle is good for up to 12 gallons of fuel or so) every few month or so just to keep things clean.

swfla

iTrader: (1)

The LS460 has direct injection and port injection. The computer manages when each one squirts fuel. So, they only operate part-time. If you've been using fuel cleaner every time you change your oil, it may be clean. As BB9 adds cleaner every few months, we can fairly certain he has a clean fuel system. But if this treatment is a rare thing, then several treatments may help. Not saying this is or isn't the issue but it's an inexpensive attempt. Plugs are due at 100k if they were never changed.
I read several times where worn engine and transmission mounts can be the cause of shaking at idle. When under power, the torque pins the engine against the mounts and eliminates the shake. Your mileage is high enough that worn mounts are a real possibility. Raise the hood, pull the cover on the engine and setup a video camera to watch the engine while you press the throttle on and off several times. If the mounts are worn, there's a lot of movement from side to side. There's a YouTube video that shows normal engine movement on the 4.6 for comparison. Low/fluctuating rpm at idle is common in this car. Usually, when electric load is introduced, the rpm goes up. Turn on headlights to introduce load and see if that doesn't solve the low rpm.

Gerf

It's 5:46 right now but no, just bored with people always whining about their car problems and seemingly unable to do a simple search to possibly find their own solution.

Protholl

How do the air filters look?

1BigDB

1BigDB

1BigDB

1BigDB

skyzhuang

Guys, thanks for the reply I just solved this problem and this is so funny, confusing, and weird... When you TURN OFF your heated seats, with AC and headlights OFF, then you will probably get this situation. However, if one of them is ON, then the idle becomes normal when it is in D(Idle in P and N are normal). There's no problem with the fuel injector, air filters, and I just simply turn on the heated seat and then solve, that's it. I also tested it again and again, the same thing happened.
I found this solution in other posts, basically, I think the principle is: The idle RPM is controlled by the ECU, and the ECU will increase the idle RPM when you turn on the electrical appliance. If you don't turn on any extra appliance, then the ECU will decrease the idle rpm. When the gear is on D and you press the brake to hold the car, the resistance exists but the transmission isn't that aggressive to keep the set rpm. So the RPM can be really low. It also tend to happen when the tempreture is low.
In my situation, when the gear is on P or N, the idle is normal. If there's something to do with my air filter or plugs, then the idle should be abnormal no matter what gears I am on.
You guys can try on your car, and I could be wrong. But I just turned on the heated seats to auto, the issue was solved.

swfla

iTrader: (1)

Great news.

Striker223

Or you can do an idle relearn lol!