Well heres whats going on. I have a low idle it useually sets about 750 RPM's, and sometimes it will shutter down to like 500-600. I've adjusted the tps and I've tired to adjust the idle but it never stays. Ive replaced all the vacuum lines so I know there all good. Is there anything else I can check?

 

have you tried to turn the idle screw at the lower right of the throttle body when you remove the intake elbow??

 

No I looked for it but I couldn't find it do you have a picture?

 

compression

 

here's the idle adjustment screw to correctly adjust idle. turn it all the way in, and adjust the screw 1/2 turn out

do you have a PFC??

 

No I don't have a PFC. The car is basically stock. And thanks for the picture I thought thats where it was but I never could get a screw driver on anything in there, Ill try again.

 

If your idle became irratic without any provocation by you, then the adjustments will probably not do anything but make you frustrated.

 

I figured this thats why I asked you guys on the forum hoping you could help me out with what I should be looking at to fix this problem. Does anyone know what could cause this problem?

 

this may seem out their but think it could be something with your fuel system

 

Clean your sticky,dirty Idle Speed Control .

 

the throttle body has 3 (iirc) mechanical settings that control idle and also affect TPS. the screw below the TB as shown above, the screw for the secondary plates and the other one near the throttle cable. i bet you one or all of them is off.

 

Is this the same screw as the air bleed screw? Cause I am having somewhat same issues with my idle with the deal that when sitting at idle if I rev the engine it goes down to about 5 or 600 RPM then vibrates for a little bit then goes back to normal around 800 or so.

 

same problem here exactly - but I haven't replaced all of my vacuum hoses yet, just 1 solenoid that was causing boost issues. When idle drops down to 500-600, does it bounce pretty steadily? And usually not respond to gas unless you half-floor it?

 

Not on my car it just shutters and goes back up to the low idle.

 

Mine has the same problem.. it idles as low as 200 rpms, I cant believe it dosent stall
I have to do a compression test aswell

 

Mine shutters also then goes back to normal after giving it a good rev at idle. I think lossening the air bleed screw will help this though. Or bumping up the idle. Maybe someone can still help us though on this.

 

No I dont have any problems like that at all. Just shutters a bit then goes back to its normal work of a nice smooth idle at around 800

 

Yea my idle is worse now..
soon as my engine gets hot my idle just drops... and was stalling on me alot today!

 

I think I have mine fixed. I adjusted the other idle screw and then readjusted the one on the front of the throttle body and it seams to be working for now.

 

Well I just went and looked at my throttle body and there is a black peice covering the screw and im not sure if I can reach in their
I have my car booked for a mechanic but it would be nice to fix it earlier

 

Same problem here, although my car is a stock '94, except for a DP replacing the pre-cat converter. In my case, I set the secondary throttle butterflies closed, and the primary throttle stop screw so that the idle speed adjust screw (air bypass screw shown in the picture above) was about 1/2 turn out at 720 rpm. With "TEN" jumpered to "GND" in the Diagnostic Connector, I set the lower of the two unpredictable idle speeds to 720 rpm. When warm, the engine just randomly moves between 720 rpm and about 1100 rpm. In either state, the idle continues at that speed. When at the lower speed, idle is smooth. When at 1100 rpm, there is a noticeable "miss," as if there is a vacuum leak. I have replaced all 68 vacuum hoses with Viton, and am convinced that they are all solidly attached. When the UIM was off the car, I sprayed both the IAC valve and the AWS valve with WD-40, and verified their rods move smoothly.

Is there any possibility this idle speed variation is caused by the EGR valve intermittently sticking open when it is supposed to be shut? IS it supposed to be shut at idle?

 

Well, I guess I can join the "same problem here" club. My car idled fine before I took off the UIM about 3 weeks ago. After removing the AWS and ISC, I put everything back together. Now after warm up my car idles as low as 600ish-sometimes even stalling. Never had this problem before. Any tips?

 

what ecu are you running?

 

Pfc

 

did you set the idle to all zeros in the power fc? once you remove the ISC you will need to go to manual idle control. You may need to adjust your idle fuel and ignition maps. When using the power fc to control the idle it uses hidden maps and the ISC.

Have you adjusted the idle bleed screw on the manifold? Or any of the other idle adjustments on the throttle body?

Chuck westbrook has some very useful tuning notes on how to set up manual idle control if you don't already have the notes.