maosla

<center><img src="http://pictureposter.audiworld.com/47646/idle_control_valve_hose.jpg"></center><p>I am also having idling issues. I replaced the hose for the ICV which was split, bought a used ICV from Shokan, and the vehicle still hunts for idle speed from 900 to 2500.
For the past 3 days, I have been driving without the electrical connector on the ICV, and the only issue is that the vehicle idles at 1000 rpm, but the vehicle drives fine, The vehicle starts fine from overnight,and any rough idling disappears quickly. I need to know if what else could be wrong. Search of this site mentions a idle speed controller, but I need to know how to test that. I will attempt to locate this weekend.
1987 5k NF engine 5 speed manual

auditech1218

ive seen that problem many times where the idle goes up to 2500 rpm, leave the car sit and it does it out of nowhere like someone giving it gas. i always replace the injector o-rings as they create a BIG vacuum leak that you wont even notice. If you dont have ALL vacuum leaks fixed the ecu will do that on those cars using the idle valve to increase the idle, unplugging the valve just prevents the ecu from raising it.

Sunthief

Mine was idleing fast till i fixed an intermitten idle switch. THe idle switch is on the throttle body, u can hear it click when you manually pull the throttle back when the engine is off. Even when it clicks it can have bad solder points inside. I fixed mine by opening it up and resoldering the points. Pretty easy fix, and cheap! Worth a shot, if its not giving you problems now it probably will later.

CARSNPLANES

I agree with Sunthief aboout the idle switch. Has been known to give erratic idle. Check also the idle screw located on the throttle intake above and near mm hose attachment. This is supposed to be screwed in all the way. Many have played with this screw to mask a bad idle problem and is another source of air in addition to the ISV, but should be screwed in all the way if everything is working correctly. This may be your high idle problem but may not account for erratic idle. If its open, screw it in and see how she behaves.

pureroundcircle

idle scew wasnt al the way in and switch needs resoldered. But for now until I get a chance to do some soldering on it, the ISV is unplugged and the idle screw adjusted so it idles between 750-1000, seems to run fine like this. I'll eventualy fix it.

audiqv8

Do you have a working AC system?? Is the climate control set to auto?? The engine idle is suppose to increase whenever the compressor kick in. Try running the car with the climate control off.

Another thing to try is to raise the hood and remove the oil cap, does the engine die?? If it doesn't then you have a vacuum leak.

maosla

A/C system works fine, and I am in Atlanta and I am primarily using only ECON setting now. Weird, but when the A/C is on for defogging purpose, 60's this week here, the idle lowers to 750. I will try the oil cap test tomorrow, but how would I find the source of a vacumn leak if I have one? The car drives fine and the fast idle is only slightly annoying.