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Nothing..that is how I recommened cleaning them out..
The valve pulses 6/7 BPM so that when it is activated, the engine does not get a large gulp of intake air that would be more than the engine could handle all at once without effecting Engine Management controls..[ ie..the ECU would read it as a lean condition vac leak b/c this air is unmetered intake air supply] ..the pulsing gets rid of that problem by letting a little in at each pulse.