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My 2.6 I-TEC has what's been refered to as an air regulator with a large black tube that goes up to the throttle body and acts as a bypass to the intake manifold. As near as I can tell it actuates at a cold start and closes after a few minutes and it appears to be electric/electronic.


That much is correct. It is activated with the ignition and bumps the idle speed and decays over time. I forget the time but it is fairly quick. You are correct about a warm engine, though it does it all the time, so it does affect warm idle as well.

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For those with more know how: Is it a device that sends/ receives a signal to/from the ECM or is this another thermal mechanical device that simply closes after a few minutes of acting as a virtual choke?


The latter. It is a two-wire device that basically just recieves power and then does it's job. There is no feedback.

Something you left out is the engine coolant temp sensor. If the water is cold (i.e. cold weather) the mixture is richened. This can be used to increase idle speed. I have never seen one fail, though, so I would not suspect it.

Most idle issues on the 2.6L come from the other things you mention (regulator almost never dies) as well as the normal mix of rotted vacuum lines and bad timing. EGR was always my biggest problem after I got vacuum and timing issues sorted out. I removed it and haven't had an idle issue since.