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It should open only a tiny bit during idling. It has a bigger range of opening for cars with A/C or an automatic gearbox, which need more air to stop them stalling as the engine is under a higher load.
Devices like this are usually calibrated/reset by the ECU as it powers up. So in it's natural resting position it may be 'off' a bit.
Operation sounds OK, although it's known on some of the bigger Volvo's for the stepper motor that adjusts the valve to burn one of the windings, so the valve is restricted in it's movement because one step is 'dead'. But as the resistance is OK this seems unlikely.
Hmm.. come to think of it.. On some cars what can also happen is that the seals between the injectors and the intake manifold or cylinder head harden, crack and thus let in air.
You can check for this by letting the engine idle and spraying carb-cleaner on the area where every injector goes into the engine. If the idle speed changes then it has an air-leak.
Sometimes you can hear leaks like this too if you use a bit of thin hose (eg. aquarium air hose). Hold one end in your ear and use the other to listen 'close up' to the different part of the intake and check for differences in sounds or hissing noises.
This is all pretty strange.. It idles OK when warm, right? The odd thing is that the ECU doesn't use the lambda sensor while idling AFAIK, so that should not have any effect.
Bye, Arno.
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