I would hope that the mods would allow this post to stay in the general forum as this venue will give this issue more exposure.

MANY posts have been created on the issue of rough idling and the part that the IACV plays in this symptom. Many have posted procedures to remove and clean the valve ... with most people reporting excellent results. BUT ... but what if the problem is and is not being caused by your IACV? I know it sounds strange but please keep reading below:

In previous posts I have detailed the saga that is my no-idling 1993 SC4. A few months ago it would (every once-in-a-while) start idling very badly ... but this would clear up quickly by reving the engine to 2K RPMs for about 5 sec. Fast forward to 3 weeks ago ... the car runs ONLY when you give it some gas ... it will NOT idle at all.

I just bought a used IACV off of Aliga (thanks Aliga for the fast shipping) to replace my unit that I thought had gone bad. I replaced the outer part (with the motor and (cleaned) valve but the problem persists. Upon the first start-up my car will run BEAUTIFULLY forever, unless you turn the engine off. Upon restarting it the engine will run very rough with an idle speed of about 300 RPM. Turning the engine off again and restarting returns the car to it's original state ... it will NOT idle and only does so when the gas is pushed.

When I pull the IACV I always retract the valve so that it is in it's full open position when reinstalled. I believe that upon each subsequent start-up the valve is closing a bit until the 3rd restart when it completely closes ... and stays that way permanently. What I cannot figure out is why.

I was hoping that those endowed with more knowledge of how this system works could help. I believe that I now have two working IACVs and that the problem is probably what controls the valve to open and close. In my ignorance I am going to assume that it is the ECU.

Please chime in with any comments or advice you have. I do not like taking my car in for work as I like doing it myself. I am contemplating one or more of the following:

1) Taking the car into the stealership for a diagnostic.
2) Trying to find someone local to Orlando (UCF area) who has a '93 compatible ECU that I can borrow to check my theory.
3) Removing my ECU and sending it off to be repaired via a service I found on Ebay.

Thank you for reading ...