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'87 Cougah 428W - ⚡Cougar7.0⚡
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Y'all stop bickering - we as an audience want to know what the solution is.
 

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Seems the IAC is working. What else could have changed to provide less air? Do you have a PCV on the car?
 

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Also check that the PCV isn't clogged or otherwise not pulling air - it's in back of the intake.
 

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PCV meaning the line that runs from the valve cover to the throttle body?
No, that's the return air line. The PCV is inserted into a grommet in the back of your intake and has a hose that goes to vacuum tee under the intake overhang - assuming stock configuration.
 

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Something changed. I suppose you can do your re-set of the idle procedure and see it if sticks. It may help to diagnose the issue, it will also satisfy our curiosity.
 

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I was thinking you could crank the throttle stop screw a set amount (so you can undo it if doesn't do what you like) to get it to idle without IAC, then plug IAC in (obviously cycle key to re-learn TPS zero position.)
 

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Oh, I thought you were familiar with this since you mentioned it earlier. You can do the below as an experiment, but it might make things worse, thus you would want to note how much you turn the screw so you can undo the change.

Throttle stop is here:
1074959


You're supposed to turn the throttle stop (clockwise in your case to increase the base idle) to where it's a certain number of RPMs below where it's set by the ECU (I can't recall and there's only misinformation published on the internet - I can't find a single legitimate site now! The internet blows as everybody has copy/pasted BAD info!). Anyway, after you do so you can turn the engine off, reconnect the IAC and see what happens when you restart it.
 

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Crankin' on the throttle stop might save you the cost of a tow. Maybe ask Indy if you have his permission to use a "flat blade". Then you may be able to drive it to the shop.
 

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Which screw is it and which way do i turn it?
I posted a picture in this thread. Turn it clockwise a half turn, then restart the engine. If you need more, you have to shut the engine off and restart or engine will think it's at part throttle. You can back off while it's running if the idle is too high. You're just trying to give it enough air to let it idle without stalling.
 

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You should probably do a cylinder balance test (throttle blip and end of KOER test? I forget) to see if you have any cylinders not firing properly. 91 is drivers side O2 sensor always lean. There's a bunch of troubleshooting for this code. Check for proper oxygen sensor ground, O2 function test (forcing rich condition while looking at O2 voltage) etc. EGR isn't there, correct?
 

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While "throwing parts" at it is wasteful and hoping on luck, I'm eager to see if Indy is willing to fly to where this person lives and show them how to do these basic tests.
 

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Shop will charge $120 and give a wrong diagnosis 50% of the time though. I've complained also, but let the person learn. Personally, I'd have turned the idle screw enough to allow it to idle and then diagnose from there, but I am a person that loses my mind when an engine won't stay running!
 

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No different then when I paid a mustang shop to do my ring and pinion and subframe connectors.
Disagree. Read WAY too many accounts of noisy gears after a shop did 'em. I did my own and spent the extra time to get everything shimmed exactly right. Quiet as a mouse. Once you buy a welder, suddenly the mounts on your lawn tractor deck will break and you'll be thanking your lucky stars that you "have a welder and know how to use it". Granted, I have an auto pit that makes doing these jobs easier, though I wish I had a lift.
 

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But it would help to rule out a clogged PCV valve, however unlikely that is. Also, being able to drive the car will allow for you to get a further feel how the engine is running and where (if) you notice issues. It could be helpful in diagnosing the issue. Also, Indy has approved of doing so as a temporary analysis tool in 2 different posts.
 

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I think you're being a little too cautious. OK, perhaps almost neurotically too cautious. :p
 

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Y'all cut that out now. :ROFLMAO: :ROFLMAO: :ROFLMAO:
 

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Been a little busy, just now got back to this childish comment.
Go **** yourself. (note:F.U.C.K)

You see, #IndytheAsshole, my post was actually a nod at you and others that show up and tries to help the poster to learn, while too many others post up with useless ****.
But in your hurry to be an *** (Note: A.S.S.H.O.L.E) to anyone you perceive as contradicting you, or having an alternate route to the same solution, you posted stupid **** (note: S.H.I.T) in response to my post.
Maybe you should seek help.
He's been banned. Probably not a good use of profanity that you've written out long-hand.
 
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lol, what did he do?
No idea. I thought I noted a " cleaned up" tone from him recently, so I got the impression he'd been spoken to. He was a bit of a db, but (at least) he didn't troll. I know some will disagree, but I hope the ban is temporary.
 
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