Fast Idle On '92 Ls400

[bamalexusguy]

I have a 1992 LS400 that I cleaned the throttle body according to instructions provided by Curt Oberg. I also change the plugs and plug wires. All went well until I started the car and it idles at around 1600 rpm. Does anyone have an idea as to what may have caused this and how to correct it?

[UCF3]

Have you warmed the car up?

[bamalexusguy]

Yes. It seems to idle even faster after warmed up about 1800 rpm.

[bicol-ini]

Yes. It seems to idle even faster after warmed up about 1800 rpm.

hello, check your idle air control valve IACV they tend to stick, anyways, if before you did the cleaning and changing of the plugs the idle was normal, try this first it might work, disconnect your battery from the negative, then wait a few seconds, this will reset the ecm, then start it see if this work, if not you have another option, remove the IACV and clean it thoroughly with a throttle body cleaner preferably chevron syntec tb cleaner, just my 2 cents worth, and hope this helps

[bamalexusguy]

I've tried disconnecting the battery with no luck. Where exactly is the IACV? It'll probably be tomorrow before I can try cleaning it. Thanks for your help.

[90LS400Lexus]

My car idles a little fast until it has been driven for about 10 miles in cooler weather. Still - it even then it is at about 900 rpms. 1600 is a little too high- even for the "fast idle" mode. Perhaps something with the throttle is sticking? Just a thought....... Good luck.

[bicol-ini]

I've tried disconnecting the battery with no luck. Where exactly is the IACV? It'll probably be tomorrow before I can try cleaning it. Thanks for your help.

hello, its right in front of the engine just below the L logo, theres a lot involve in taking this part out, if you have access to a repair manual much better but its worth it the part alone costs like over 600 bucks

[bicol-ini]

I've tried disconnecting the battery with no luck. Where exactly is the IACV? It'll probably be tomorrow before I can try cleaning it. Thanks for your help.

hello again, also one thing probably happen was when cleaning the throttle body some of the gunk or deposits went into the IACV, thats why youre getting the high idle even after warm up i think normal idle is like 600 plus or minus 50 rpm, dont qoute me on this but somewhere in this ballpark,

[dpeck]

I've tried disconnecting the battery with no luck. Where exactly is the IACV? It'll probably be tomorrow before I can try cleaning it. Thanks for your help.

hello again, also one thing probably happen was when cleaning the throttle body some of the gunk or deposits went into the IACV, thats why youre getting the high idle even after warm up i think normal idle is like 600 plus or minus 50 rpm, dont qoute me on this but somewhere in this ballpark,

If throttle body is ok try checking to see if a vacuume hose got knock loose in the process the engine computer will raise idle speed if a vacumme leak is present to keep ingine from stalling

[bamalexusguy]

Throttle was sticking from where I jammed it open to clean the throttle body. Sprayed a little WD-40 on it and everything is fine now. Thanks for the suggestions. Hopefully one day I can help someone the way you guys helped me.