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Can anyone help me with this issue I am having. I have a feeling my car idles too low (I think its 400rpm) and it has a very slight shake in the engine because of this.
To compensate I often run the aircon which lifts the idle speed by 100rpm.
Has this happened to anyone before and can I just adjust the idle by a teeny bit to fix this issue? Or could this be a faulty plug issue or afm or something like that
I'd first make sure the air filter, and air filter box where spotless. Then I'd clean the MAF using the appropriate spray cleaner. Then I'd clean the throttle body using TB spray cleaner and rags. Then run a couple of cans of techron concentrate fuel system cleaner thru the gas. This is all easy diy stuff. Buy the right chemicals, take your time use clean rags, etc. Or have the dealer or local shop do it. Once you are done my guess is that the engine will run smooth - barring a more significant problem like bad spark plugs, O2 sensor, etc. But at least make sure your fuel / air system is nice and clean first.
All that sounds like a lot of work lol. I would check with a reputable mechanic to see if the idle speed is adjustable. Might just be a simple fix with an OBD II scanner.
I had the same issue - the car would idle sometimes at 750, then the next time it would be 400 - with the accompanying minor shake. According to my mechanic, it's a dirty throttle body - which should be cleaned every 48K Kms or 30K Miles. So have it done, or follow Jabberwock's instructions - or there is another thread here: https://www.clublexus.com/forums/ls4...-cleaning.html
if you want to do it yourself.
I have the same low idle issue with my 01' 430 UL. I cleaned the throttle body after reading Jabberwock's post, but it did'nt improve the idle. To date I have not been able to find a fix for the low idle, but I have found a way to raise the idle. I noticed that when I turned on the driver's seat heat or cooling the idle would go up from 400 to around 600. Now that summer is here and I'm using the a/c more, the seat fan is off for now.
If anyone finds out a sure fix for the low idle, please let me know!
I have the same low idle issue with my 01' 430 UL. I cleaned the throttle body after reading Jabberwock's post, but it did'nt improve the idle. To date I have not been able to find a fix for the low idle, but I have found a way to raise the idle. I noticed that when I turned on the driver's seat heat or cooling the idle would go up from 400 to around 600. Now that summer is here and I'm using the a/c more, the seat fan is off for now.
If anyone finds out a sure fix for the low idle, please let me know!
The seat heat/cooling is powered only by an electrical current, nothing else. How that affects the idle speed seems strange, but would indicate an electrical problem of some kind.
SH430 I have not attempted to fix this issue yet. Did you do any other troubleshooting?
Well, I would'nt call it troubleshooting, but I asked the service advisor at the local dealer (he is a former mechanic) about the low idle speed, and the best he could come up with was (no suprise) cleaning the throttle body. I'm wondering if the throttle position sensor could have somethig to do with it, but the problem dos'nt bother me enough to start throwing money at it yet.
Idle speed should be regulated by closed loop system. So adjusting tp sensor may not help.
Also, turning seat heater on draws much current, causing the computer to add revs to maintain power levels.
Maybe alternator related ?
Guys.. 04 Does the same thing. Based on what I can tell, the engine management system kicks the idle up (in gear that is) when the alternator is being taxed by either the seat cooler/heater or the headlamps. Obviously it also adjusts itself when the AC is running.
My 2005 also idled at about 400 rpm. I cleaned my throttle body and mass airflow sensor this morning and I'm now idling at 800 rpm. Much more inline with what I would expect it to be. Hopefully this holds.
I have lexus LS430- 2003 and I'm facing high RPM problem.
Last week from the garage i have changed my car gear transmission, after that my car giving me high RPM all the time,
so engine making more sound.
anybody can give any suggestion will be highly appreciated.
Thank you
According to the repair manual, here are some of the causes for high engine idle speed. Your transmission repair work may have disturbed one or more of these systems. Are you getting any DTC (Diagnostic Trouble Code)? Sometime, a hard reset, by disconnecting the negative battery cable for a few minutes, can/will restore factory default settings.
LS430 Idle speed
