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Old 01-31-2016, 02:24 PM   #1
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Bad iac or something else?

When start it idles really bad and stalls if I don't hold the clutch in, I unplugged the sensor that connects to the iac and it makes the same symptoms with or without it being disconnected. Bad iac? If the iac was working wouldn't the car just stall as soon as you disconnect the sensor?


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Old 01-31-2016, 03:02 PM   #2
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Have you checked for codes?
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Old 01-31-2016, 03:04 PM   #3
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No check engine light


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Old 01-31-2016, 03:21 PM   #4
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Just checked no codes


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Old 01-31-2016, 03:42 PM   #5
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I'm betting iac

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Old 01-31-2016, 03:47 PM   #6
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Only does it when I start it btw after a few seconds it goes away


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Old 01-31-2016, 03:56 PM   #7
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It could be the IAC, but it could also be the faulty negative battery cable causing some "gremlins".
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Old 01-31-2016, 03:59 PM   #8
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Quote:
Originally Posted by straybullitt View Post
It could be the IAC, but it could also be the faulty negative battery cable causing some "gremlins".

I replaced the bad ground yesterday so that's all good.


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Old 01-31-2016, 04:08 PM   #9
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I assume that the idle relearn procedure was completed then.

Possibly a problem with the IAC. If you decide to replace it, I recommend purchasing a Motorcraft.
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Old 01-31-2016, 04:09 PM   #10
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Bad iac or something else?

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Dumb question. Can it be the gasket?
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Old 01-31-2016, 04:26 PM   #11
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Could be the gasket looks abused

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Old 01-31-2016, 04:46 PM   #12
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My friend is parting out his . I'll be getting his iac


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Old 01-31-2016, 05:41 PM   #13
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Let us know if that fixes it.. As I am battling the same issue right now only mine doesn't die just a really rough high idle, seems like it only does this when the heater is on or a/c


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Old 01-31-2016, 05:47 PM   #14
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Mine only does when I start it for about 10 seconds if I don't give it has it'll stall.

Also it seems like no one sells the gasket


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Old 01-31-2016, 05:58 PM   #15
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Quote:
Originally Posted by alecas447 View Post
Mine only does when I start it for about 10 seconds if I don't give it has it'll stall.

Also it seems like no one sells the gasket


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Lol.
I've run into this same problem.
The gasket manufacturers call the IAC an "Air Bypass Valve". Ask for an air bypass valve gasket.
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Old 01-31-2016, 06:00 PM   #16
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Quote:
Originally Posted by straybullitt View Post
Lol.

I've run into this same problem.

The gasket manufacturers call the IAC an "Air Bypass Valve". Ask for an air bypass valve gasket.

I found them at autozone going to pick it up in a little bit for $5


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Old 01-31-2016, 06:44 PM   #17
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Bad iac or something else?

No One had them in stock

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Old 02-01-2016, 01:38 PM   #18
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Quote:
Originally Posted by alecas447 View Post
No One had them in stock

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Replaced the gasket. Still isles bad upon start up


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Old 02-01-2016, 02:55 PM   #19
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Have you checked for vacuum leaks

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Old 02-01-2016, 05:15 PM   #20
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Did you replace the IAC?
Or just the gasket?

And you need to disconnect the negative battery connection every time that you replace, or clean, any of the components on the engine, so it can relearn the idle.
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Old 02-01-2016, 05:44 PM   #21
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Quote:
Originally Posted by straybullitt View Post
Did you replace the IAC?

Or just the gasket?



And you need to disconnect the negative battery connection every time that you replace, or clean, any of the components on the engine, so it can relearn the idle.

Just the gasket for now


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Old 02-06-2016, 07:55 PM   #22
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Maybe, a dirty throttle body? I cleaned mine two weeks ago and it idles better now.

I did not know it was that bad dirty until I wiped the back side of the throttle plate.


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Old 02-10-2016, 11:52 AM   #23
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I'd do an idle relearn first. How many miles are on your car? If the idle relearn doesn't fix the prob, I'd get a new IAC. Chances are that it's the original IAC. Buy one locally though. I bought a Motorcraft one from Rock Auto and it turned out to be bad lol. I've bought some AC Delco parts from Rock Auto that were bad too. not sure wtf is up with that, but thought I'd pass it along. It can certainly be something else, but it sure seems to me like an IAC issue.
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Old 02-14-2016, 01:35 PM   #24
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91k miles on the car

Replaced the iac and tps and fuel rail sensor. It still idles bad when I start it up


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Old 02-15-2016, 09:01 PM   #25
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It started happening when I changed the plugs to auto lite 104s. Maybe the bad idle is that they aren't gapped to where they should be? Is this a possibility


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Old 02-15-2016, 09:11 PM   #26
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It could be that your 1 or more of your COP's or the boots are bad. Usually it will throw a code when it's missing out. I guess it's possible it's got just enough spark to idle without throwing a code. As war as the plugs, did you check the gap before you put them in? It should be fine if they are around .052 to .054. The first time I changed my plugs, I didn't get my COP's down on the plug securely and it idled bad, like it was missing. But, the CEL lite up too. I assume you aren't getting a CEL..?


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Old 02-15-2016, 09:49 PM   #27
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Quote:
Originally Posted by rcodemach1 View Post
It could be that your 1 or more of your COP's or the boots are bad. Usually it will throw a code when it's missing out. I guess it's possible it's got just enough spark to idle without throwing a code. As war as the plugs, did you check the gap before you put them in? It should be fine if they are around .052 to .054. The first time I changed my plugs, I didn't get my COP's down on the plug securely and it idled bad, like it was missing. But, the CEL lite up too. I assume you aren't getting a CEL..?


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I'm getting no CEL and no I didn't check the the gap on the plugs before putting them


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Old 02-15-2016, 09:57 PM   #28
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Another thing that goes bad and makes the car idle poorly and almost stall out, especially when coming to a stop from a higher gear is the TPS. If the IAC and TPS are both worn out, it's going to feel like it's barely able to run.
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Old 02-15-2016, 10:01 PM   #29
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Another thing that goes bad and makes the car idle poorly and almost stall out, especially when coming to a stop from a higher gear is the TPS. If the IAC and TPS are both worn out, it's going to feel like it's barely able to run.

I replaced both and even the fuel rail sensor and nothing still does it


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Old 02-15-2016, 10:05 PM   #30
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I'm getting no CEL and no I didn't check the the gap on the plugs before putting them


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You really want to check them, because they can get dropped before they get sold. Did you happen to put any dielectric grease on the boot of the COP's? That will help ensure a good connection to the plug. Also, those clips on the COP wire connectors can get broken. They can disconnect themselves easy when they break off. Two of mine are broke lol. It's the heat that makes them brittle. What I do is move the wire harness a little so that its kinda holding the connector in the COP. Try messing with those two things before pulling the plugs and checking the gap.


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Old 02-15-2016, 10:17 PM   #31
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You really want to check them, because they can get dropped before they get sold. Did you happen to put any dielectric grease on the boot of the COP's? That will help ensure a good connection to the plug. Also, those clips on the COP wire connectors can get broken. They can disconnect themselves easy when they break off. Two of mine are broke lol. It's the heat that makes them brittle. What I do is move the wire harness a little so that its kinda holding the connector in the COP. Try messing with those two things before pulling the plugs and checking the gap.


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Nope I put no grease when I put the coils in. As for the connectors they same, but I did notice that they which I completely forgot that one of the connectors for cylinder 5 the connector isn't clicking when I connect it the other ones click fine except for that one. Can gay be such an issue to cause the poor idle on start up? If so, how much do one of those connectors go for?


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Old 02-15-2016, 10:26 PM   #32
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The one that doesn't clip zip tie it down see if that helps could be a bad connection

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Old 02-15-2016, 10:29 PM   #33
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Nope I put no grease when I put the coils in. As for the connectors they same, but I did notice that they which I completely forgot that one of the connectors for cylinder 5 the connector isn't clicking when I connect it the other ones click fine except for that one. Can gay be such an issue to cause the poor idle on start up? If so, how much do one of those connectors go for?


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IDK, I've never seen them for sale. I haven't looked real hard tho. If you hold them together right for 20-30 seconds, many times they will stay connected because of that rubber seal on them. It kinda sucks them together. I had to wiggle the harness on mine to get it to put pressure toward the COP to keep it connected.


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---------- Post added at 11:29 PM ---------- Previous post was at 11:28 PM ----------

Quote:
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The one that doesn't clip zip tie it down see if that helps could be a bad connection

^^^ This


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Old 02-15-2016, 10:34 PM   #34
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I noticed you have an Accufab TB. Did you recently put that in? Aftermarket TB's are sometimes the cause of idle issues combined with certain cold air intakes. If it has not idled right since messing with the TB or replacing the CAI, check for leaks in your intake between the MAF and the TB. Make sure your MAF wiring is connected and not damaged.


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Old 02-15-2016, 10:34 PM   #35
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Bad iac or something else?

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