This is a continuation of my quest to solve the high idle problem of my '91 LS. This time I have a little more info.

The idle speeds I list below are when the car is in park. When the idle is fast (at 1200, or so), it runs a little rough and I can faintly smell gas. Running rich?

The problem is worst in the winter. The idle pretty much stays at 1100 to 1300 ALL of the time.

When it's warm outside, the fast idle is 1100-1300 when I first start up. After driving a while, it will drop to the normal 750. However, if I turn off the engine and restart, the idle jumps back up to 900-1200. It can vary quite a bit, though.

I've had the wires and plugs replaced (unfortunately, I don't think they used OEM wires like I requested ). I then replaced the caps and rotors, myself, with OEM parts. I've also started replacing vacuum hoses. I found the PS-idle up hose had a split on the connection to the ISC and replaced it along with the hose that connects to the intake air connector pipe.

I suspect the mechanic who replaced my timing belt is the one that cracked the hose. I also believe he's the one that did a number on the hose connector to the air connector pipe. He broke it off and then glued it back on, the idiot. So, I redid the connector with a brass 3/8 to 3/16 connector fix.

Anyway, I'm thinking maybe I've got another cracked hose somewhere. Any ideas where to start or any other suggestions?

 

had the same problem before. Check out the link on this topic. http://www.lextreme.com/forum/viewtopic.php?t=18

 

Picture of IVC

 

Thanks, Lextreme. That sure sounds like it could be the problem. So, do you think mine could be going bad or is it possible that a cleaning would fix the problem?

Looking at my Lexus shop manual, I see it referred to as the ISC valve (idle speed control). We're talking about the same thing here, right?

If so, it says the first step to removing it is to drain the coolant. Do I really need to do this or is it just so that you don't have dribbles of coolant coming out when loosening the water by-pass pipes?

 

we are talking about the same thing. You will need to remove a small hose from the radiator. The radiator hose lock is blocking the ISV screw. Its a 5 minutes project. I think in your condition, cleaning will help......

 

Thanks, Lextreme, I'll give it a try.

So, should I lubricate it with some kind of lubricant as well or just clean and "work" the springs?

 

please PM me if you need further information