yenanlexus

I found the tps after took of the tp. tps is connect to the tp on the right side. I try to adjust the tps w/ the needle put behide the connetor of the tps and play around w/ it. I did adjust the tps to the right or left to get the reading of .8 ohm on digital multi meter. and then i connect every thing back. I start the car wait until it warm to the normal. it not low any more, but driving stall and not smooth as before???.
I try to find the idle control valve. I can't located.

Chuboom

I have the same issue but my car stalled on me on the hill. Thats when i notice my rpm meter was messed up. Does anyone live in San Jose Ca, that can help me with mine? I am not a car person... =/

yenanlexus

The IACV is locating in the middle of the intake manifold in the intake chamber. Check the engine mount first before you mess w/ IACV it cost more than $700. For the idles too low, change the engine mounts, all 3. Now, my car no more low iddle, and run very smooth. I has it changed in Dealer: cooland flush, front brake change, and all 3 mounts. Total $1119.

iamviolet

motor mounts for low idle?

lexie

yeah! how the mounts has anything to do with the idle? my idle is around 400 too but engine no stall though.

farquad

hey all.. i have a similar problem, except my car dies when there is a load on it.. as in turning the ac on while idling or in stop and go traffic will likely kill my battery
i have replaced both the battery and my alternator.. here's my problem.. normally when you turn the ac on or put a load on the car, the rpm's go higher to compensate.. instead in my car, the rpm's drop even more.. so it idles realllly low with the load on the battery, it idles even lower with the radio AND the ac on.. pretty much kills my battery in city driving.. on the highway it's fine cause of the high rpm's
i'm hearing a lot about the throttle body and the tps.. are these symptoms related to those two things?
thanks in advance

ctuba

Did you ever find out what the problem was?? I have the same issue with my 1999 ls400 with the low idle speed and dying.

mattylex77

i just bought a 99 ls400 with 95k miles on it. warm Idle in D no headlights no AC, tach reads 200 rpm with accompanying harsh vibration coming from engine compartment that smoothes out in N at higher rpm 600~. As long as i run it like this in the past week it has not stalled.
I took it to the shop and they said the scanner was reading 500~600 rpm and that my tach is bad. BUUUT the tach behaves properly under all situations and moves the right way when it the shifts or i go into N or R, whatever. But usually when i start the car cold it doesn't move and then i have to whack the dash, which immediately brings it to life.
the car also has reasonable torque when i take my foot off the brake at idle, but not quite the torque of an engine running at 600 rpm. the mechanic suggested it was just the motor mounts causing the problem but i wouldn't expect them to be that bad at this mileage.
so to summarize.
reasons why i think its the engine causing the prob: don't think MM's could go this bad at this mileage, don't think the tach is broken.
reasons why the mechanic is right: the scanner said so, the car actually moves when i take my foot off the brake and i want him to be.

Also this is a florida car that spent the last 4 years in new york perhaps ECU caps are the culprit in the humid florida climate

RugbyDad

I believe that new York is in the top 5 most humid States in the country. Up there with Louisiana. From what I've read ecu caps are more prone to failure on the earlier gens. That being said it's a good preventative measure to take.

I experience this same issue to some degree. Not 200 rpms.. More like 450 with no Ac and no lights. My motor mounts are going bad and I'm @ 82k on a 2000.

mattylex77

just cant believe an ls400 tachometer would be inaccurate, motor mounts ok but the tach??? perhaps an ecu caps thing. I would love for the esteemed lscowboyls or yamae to chime in on this one. i also have an intermittent check engine light that is apparently from a lean o2 sensor. maybe related?

sha4000

iTrader: (1)

Run a couple of Chevron techron fuel treatments and clean your MAF sensor for the intermittent code.

mattylex77

thanks for the replies, wouldn't simply just replacing the o2 sensor fix the issue? or is the dirty MAF the underlying problem

RA40

iTrader: (6)

Motor mounts...

Any error codes? How's the fuel mileage? Many possibilities to randomly run off. Check the vacuum hoses, leaks there and especially to the intake plenum are critical.

sha4000

iTrader: (1)

Cleaning the MAF and running the Techron chevron gas cleaner is meant to stop the intermittent code from reappearing and most likely will not fix the underlying issue. It did however fix my SAME issue of idling low, running rich and car dying so give it a try. Make sure to use a MAF cleaner though.

Yamae

I quite agree with Mike.
I also suggest you to clean the throttle body and the air mix path to injectors. For models 98-00, the ECU capacitors cause the AT shifting problems first in most of the cases. Your problem is not directly related to ECU capacitors, I assume. Of course it would be good to replace capacitors as a preventive measure like I did. But this will not be removing your problem, I can imagine.

Don't you notice any slow acceleration then an unexpected speed up when you turn a corner or slow down at a speed bump? A badly clogged throttle body confuses the ECU and causes this symptom when you speed down then accelerate. In other words, the symptom is described that the gas pedal does not respond as you expect once you speed down and then speed up.