My rough idling engine quits when I unplug my IAC. Only Motorcraft brand IAC's?

Hi folks,


First, is this normal? Most posts that I have read seem to suggest that a bad IAC would allow the engine to continue to run when disconnected. My mechanic friend seems to think the IAC is at fault.


Secondly, only Motorcraft IAC's? I purchased a cheap one from RockAuto and it didn't seem to fix the my poor idling and driving conditions (which include my engine losing power and cutting out in the middle of drive). I've heard that I should stick with Motorcraft brand IAC's. Is this true?


This problem by the way wasn't present until after I gave my truck a tune up.


Is there anything else I should know/try? Please let me know...


Thanks

My engine was stopping at idle with the bad IAC valve. I was pressing the gas just to keep it from stalling.
I am now using the Advance Auto parts one (made by BWD) for 2 years now. No problems.

IAC Stalling

BHop - 2000StreetRod has some good posts on this topic.
The engine dying when the IAC is unplugged can be normal. That's what my '97 4WD EB with the 4L SOHC engine does, even after I replaced it with the Motorcraft exact replacement part.
2000StreetRod suggests resetting an adjustment screw that will maintain the idle if the plug is disconnected. He has a thread on this topic, if you do a search, you'll find it.
It could be a vacuum line that may have been disturbed.
Exactly what did you do to tune it up? What engine do you have?


Good luck,
Dick

When I gave it a tune up, I did just that, replaced the plugs and wires.


It was suggested to me before in a previous post that I forgot reconnect a hose. However, I looked everywhere, and so did my mechanic friend. Couldn't find anything.


One thing I did notice about my old stock IAC is that I would hear a whistling /air sucking sound when I apply the accelerator. With the new one, I don't hear that same sound when appling the accelerator.


This adjustment screw sounds interesting, but I didn't touch anything like this when I gave it the tune up.


I have an 4.0 OHV engine.


Anything you can provide me with would be greatly appreciated!

Hoo hoo hooooo! I think I just fixed my problem!


A shot in the dark, but worth while!


I just opened up my intake hose.... the part close to my K&N air filter. A FREAKIN BALL OF NEWSPAPER FALLS OUT!!!!! UNBELIEVABLE!!!

(Note: I remembered doing it for the other end of the hose a few months ago!)


This would explain the rich smell of gas, Harley Davidson idle, and why nothing would happen when I gave it gas.


I'm an idiot, yes, but a happy idiot!


Now, should I bother reseting my computer?


Thanks everyone!!! :

Wtf ???

I placed rolled up balls of news paper on both ends of my intake hose to prevent dust from entering. I decided to remove the intake hose to make more room as I go about the mechanical work.


Yea I know, wtf indeed...