I had my IAC off the other day and noticed that in the fully closed position it still lets some air through. I cleaned it out really well thinking it might just a little dirty and not sealing fully. Still lets air passed. Is it normal to have some leakage or should it be 100% sealed when its closed?
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here's a pic of the gap. It should be fully closed when disconnected from the truck correct? I can pull the valve down and seal it with my finger but it springs back up and sticks in this position.



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Well I yanked it back off and soaked it in wd-40 overnight and now it closes fully and the spring snaps it shut with a nice bit of force so I guess the valve was sticking and keeping it open. It functioned fine on the truck except it always had a slightly high idle (about 980) when warm so maybe this was why. Ill see how it works once I knock the crud out of my eyes.
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Sorry I missed it, yes it should close all the way but some do not, it doesn't become an issue unless it leaks enough air "closed" so it prevents computer from setting warm engine idle RPMs

4cyl engines have higher idles because of the balancing, hard to get a smooth low RPM idle with 180deg balancing of a rotating mass, 850rpm would be about it for smooth idle and lower emissions
Lower emissions is also a factor, the lower the idle the higher the emissions

 

Thanks ron, I took it for a drive to get it warmed up and the idle went from 980-1000 hot to 860-880 hot, so definitely stuck a bit. Wd-40 did a way better job getting it working than regular carb cleaner did! So learned something new there!