Crazy Idle

[shizgriff]

What's up everyone?I went today to look at a 1991 LS400 with 185.000 miles on it.When you start the car the idle goes up and down and even after at warms up it still does it.When you put it in drive it stops but the idle is still high(1000-1100).The car runs very good has full power Cd system and the whole 9 yards.First is this a good deal for $4,000 and second does anyone know what could cause this to happen?

[SKperformance]

could be a lot of things related to many parts and vacume leaks as well

have you tried fixing or looking at anything?

or done any regualr manitance on all used car purchase parts?

[shizgriff]

I didn't check anything because I didn't but the car yet.I was trying to see if it was worth buying and if it would be costly.

[99lsguy]

I'd find out what the repair estimate was..................deduct it from the $4K........and go from there.

An ECM could be costly if it's whacked out......

My last advice......keep shopping ;)

[fatman]

If I was you I would still be looking (you don't want to fall into a money pit), was checking out my other favorite website EBAY and found this for you to look at and it is in your area

http://cgi.ebay.com/ebaymotors/ws/eBayISAP...TRK%3AMEWA%3AIT

good luck and happy hunting

[shizgriff]

Fatman it's funny that you showed me this i'm supposed to meet with this guy on wednsday to see this car.We talked and he told me that I could have the car for $5,000.

[fatman]

but you you might be able to get it for less, depending on the final bid, I would go meet the guy drive the car, have it checked by a mechanic, then if all checks out put a max bid of 5k on it you never know, it might only bring 3500.00 :cries:

[VBdenny]

The throttle body is clogged. Oberg made a great tutorial on how to clean it complete with pictures. If you can't find it, PM me with your email and I'll send it to you on PDF.

Very cheap and very easy.

Denny

[moune]

I have the same problem with my 1990 LS400, can some one please help. Thanks

[silvermate]

first check all of the vaccuum hoses to make sure they are connected properly

if thats not it, then its probably something in the bad in the ignition...ie....plug, wire, dist cap, rotor, ect.......

cleaning the throttle body won't help that problem, the throttle body doesn't get all the way clogged it just gets significant carbon buildup on the inner walls and throttle plate,,, when i cleaned mine it l improved the throttle response,,,, it might make it idle a little smoother

but the surging type of feel you get at idle is most likely something from the ignition or vaccuum line

[jakeroux]

I just bought a used 92 LS 400 over the weekend with this identical "crazy idle" problem. Took it to the local Lexus dealer today for a general checkup and they dignosed this as a "gunked up" idle cnotrol valve. Quoted $900 to replace, but offered that I might be able to get it cleaned out on my own with injector cleaner. I told them to do their injector cleaner service for $69 and let's see what happens. Will post a reply if I get it corrected. In the mean time, if someone could PM me with the tutorial from Oberg that Denny mentioned above, I'd appreciate it. I can't seem to locate it doing a search.

Thanks,

Jerry

92 LS400 155,000K

92 Toyota MR2 178,000K

Running on faith....

[vyhanh]

http://www.lextreme.com/tb.htm

[moune]

I have also cleaned out the throttle body, yes it did run a little smoother, but didn't take care of the crazy idle problem. It still kept on jumping up and down. I have it in the shop right now and I was told it was problably a vacuum hose that is lose or busted. I'll provide more information as soon as the mechanic gets back with me.

[jakeroux]

Thanks for the info to both. Got mine back yesterday evening and the problem may have been slightly improved on it as well after having the dealer do the injector cleaning (with 44K fuel addative, which I think I saw referenced elsewhere on this site in relation to this problem), but is definitley is not fixed. Their recommendation was "needs ISC valve", which again was quoted as $900 for parts and labor. Would be very intersted to find resolution to this. By the way, the dealer mentioned nothing of loose vacuum hoses on mine, this apparently after a thorough inspection.

[silvermate]

what is the ISC valve????

[jakeroux]

I believe "idle control valve" is what the service rep told me yesterday. The ticket just listed "ICV" as needing replaced. He also indicated that the problem with this valve was related to the trac control light staying in the off mode.

I also notice the idle revs staying probably higher than nomal when cruising, as well as a bit of stuttering at highway speeds. When just cruising, the idle will keep the car at about 40 - 45 mph without my foot being on the gas. I tend to think the ICV valve diagnosis may be correct, just don't want to have to ante up the $900 to replace it if I can avoid it.

[jakeroux]

Oops, sorry. ISC is what was listed, which doens't exactly translate to Idle Control Valve. Regardless, some type of valve related to idling.

[moune]

I finally got my car back from the mechanic yesterday and drives very smooth now. After a dianostic check, it ended up being the "idle speed control valve". The valve itself will cost you around $700.00, but the mechanic knew a way to modify and adjust it so that I wouldn't have to buy a new part and it only cost me $150.00 for the whole thing. My car runs great now and he warranties his work. By the way I have a 1990 LS400 with 210,000 miles on it. I also have a xenon body kit, tinted window, 18" chrome wheels, and a custom pearl white paint job on it. It looks new and runs new. Hope this answer some questions.

[silvermate]

idle control speed valve, did he show you where it was located? if so could you elaborate on where it is....

i wander if he was talking about the throttle position sensor on the throttle body, i know you can adjust that to make more or less idle.........

[moune]

Sorry, he didn't get a chance to show me where it was located, but I assume it's somewhere near the throtle body.