No worries! I know what frustration feels like.I have a theory on these FX5's just based on user reports. I think the motor might be TOO strong for a lot of situations. That motor is going to create a lot of vacuum which in most cases is good but if there is too much resistance it will pull air SOMEWHERE and it's trickier to locate vacuum line leaks because when you try to find them with positive pressure you usually cant find them. Most o-rings and pressure seals are based on pressure to "squash" a silicone or rubber seal/gasket to establish the seal. More pressure = better seal. This isn't the case with vacuum hoses.
I think it may have been sucking air in from the valve that connects the input hose to the filter, because when I would go over there that is where it would sound like the air was.
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