My wife and I ditched her 99gs3 for a 02' gs430 about three weeks ago.
Everything seemed normal for a while, then the idle seemed to drop down to around 250-300rpm and the car is shaking like its going to stall. And it squeeks very faint all the time like a bad power steering pump bearing. Its not belt squeal

I do all work on my own cars, for the last 15+ years. Turbos, built motors. You name it.

I decided since this car still has factory warantee left that I would have my wife take it in to the dealer to check the idle.
To my suprize they said they found no problem. WTF. The guy says the car is supposed to idle that low and that it is the belt thats squealing because its dry rotted. Ah pal I got news for you. The belt is new. And Ive driven other cars that dont idle like that. I know I cant compare a I6 gs3 to the v8 but I have a 94 gs3 that has 168k that idles rock solid like the day it came out of the factory.

To top it off, my wife told me they fixed nothing. I took it for a drive last night. It drove like crap. First when I fire it up, it now idles at 1200rpm. Not the normal cold start idle speed is it ? Cause it does that for like 10 minutes.
Then the idle drops down to 400rpm and still does the "I almost want to stall on you" BS. The service guy saw a new toyota battery (we bought it at a toyota dealer) He proceeds to tell me that the cars program themselves after you disco the battery. Like no **** dumbass. But not for two months.

Before we dropped it off I filled the tires to 38psi cause they were all low. Since we got it back, it was wandering all over the road. I decided to check the tire pressure again. To my surprise one tire was filled to 50psi !!!#%&#^ WTF.
The other three were 46.4 according to my gauge. Max pressure is 44 and I left them set at 38, why would they change that.

Gawd im pissed

What do your gs3/4/430's idle at. Please tell me im just over reacting. I would expect this from any other dealer which is why ive never taken any of my cars to a dealer, ever.
I was hoping/expecting this would be a more pleasent experience.

 

At cold start, it does idle high, around 1200 range, then it idles to about 6-800...

I have no idea how your tire pressure got up that high, that is really dangerous...

The GS4's in general seem to idle louder than the GS3's...

 

How long does it idle at 1.2k though. This thing will drive down the road like the CC is on for like 10min

 

Until it warms up, maybe 5 minutes or so of driving, when idle, it takes longer for it to warm up...

 

Have you cleaned the MAF sensor or throttle body? Those are two good culprits for a low idle condition.

 

My car idles a bit rough at times, i don't know why, i've cleaned the TB, but soon I'm going to do a full tune up, replace all fluids and plugs, etc. hopefully this will help with my little rough idling...

 

What I dont get is this wasnt a problem for a while, it worked fine for a few weeks and then all the sudden theres a problem. The car only has 48k on it.

Still kind weird that they are telling me that theres no problem when there is clearly a problem that it idles at 250rpm. The other 4's and 430's idle around 600. Then the tires and the squeal...

 

I would suggest change dealerships that you bring the car for service. If that is not possible atleat switch service consultant. Start by discussing what they did wrong. On your part, you will have to use tact as very few people appreciate a customer who may know more than what they are supposed to know. Try not to make it personal, but limit the discussion to the issue and leave the guy enough room to let him work to the conclusion that you have already drawn without making it sound that it was "your idea".

Gone are the days when we had idle set screws. Due to emission standards, the dealer wil lnot adjust any thing, but simple replace sensors, and they generally dont do that till they get a reading of fail. Low idle is not very uncommon, and the easiest way to fix that is to have the AC on.

If you go in for tire rotation, always re-check the torque and air pressure.

Salim

 

Thanks Salim. Thats what I have planned. Im going to speak with the service manager first to see if he/she can help me out.
Your right, I do tend to get worked up with how some service techs, parts people and salesmen treat customers that do know what they are talking about.
Its so frustrating to learn that there are so many people getting taken advantage of.

Is it really that common for you guys to have low idle ? If thats the case, ill live with it. Though I do find it weird that it just presented itself as a problem out of the blue.

 

the lowest the idle should go is 400rpm at idle in D with ac and headlight switch off. if the motor mounts are worn(mine were at 36k) you'll feel a vibration.

 

my car idles around 500-600 RPM.

 

Did you feel a vibration at any other rpm ? Im confident that this shaking is due to the 250rpm idle.

 

same here.. after a couple min. warmup in the mornings.

 

My car idles at about 600 but when startup on a cold morning it will be at about 1200. I would check your MAF sensor first thing.

 

definitely try to work this out through the dealership. But if they wont help you call lexus. The idle on the car in perfect condition should be 700. That is what my car idles at. Everyone that is a lil bit lower experiences a shake. When I start up the car it idles at 1200 and that is the max that it has ever went. Good luck getting this problem solved. Keep us updated on what happens.