LCAN

Anyone out there have any suggestion for high engine rpm ( 2000 RPM at Idle) on a LS400 year 2000

I had a problem with theRPM fluctuating from 900 down to 500 and back to 900 when the a/c was turned on. After scanning I got two solar codes 1421 &1424 however many of you suggested to ignor since these were common & did not realy pose a problem. Some suggested to clean the throttle body with carb cleaner which I did and now the RPM's run up to 2000 and stay there. I did a scan but no codes not even the solar codes. I'm at a loss I would appreciate your suggestions I'm in the middle of SE. Asia and don't have anyone here with the required knowledge or experience with EFI vehicles

Yamae

Try resetting the ECU. It can be done removing the negative battery terminal for 15 minutes or more.

After this, you need to drive some 10-30 minutes depending on the traffic situation. It would be better to drive in the city because you often need to stop and run. This is to educate the ECU to settle down to the proper idle rpm.

PureDrifter

iTrader: (10)

clean the idle ports on the throttle body

steve2006

He already has PD

steve2006

Reset ECU as mentioned if still present make sure all the vacuum hoses have been refitted correctly and are not damaged.

YoshiMan

How does your temperature gauge look? Mine had a high idle problem because it had a faulty coolant temperature sensor, and the thermostat was stuck open, resulting in the car being stuck in "warm up" mode.

LCAN

Temperature readings normal engine not overeheating n running too cool

I reset the ECU several times. I'm still trying to resolve the problem. I have received some additional infdo from fellow members of Club Lexus so I will try out tgeir suggestions and see what transpires.

Lcan

PIONEER

iTrader: (2)

does the RPM also jump if you move the steering wheel left to right? could be the idle air control valve.

sshhlexus

I have a similar symptom with my '93 LS400. First I have ECU issues mentioned on other threads.

On drive idle seems okay, Park idle seems high, I cannot read the rpm as the tachometer only reads zero. I'm going to try on neutral(N) later if it makes a difference. Gotta be closer to home if this causes the engine to die out.

LCAN

Thanks for all of your support. I did as you suggested. Cleaned the Throttle plate and passages into the throttle body and cleaned the MAF engine ran better however still had high idle issue. Found there was a vacuum line had a split at the end Replaced several vacuum lines now purrs like a kitten. Tyhanks all of you Club Lexes guys for you kind input.

Cheers LCAN