I would check for cracks in the hoses , Especially the PVC valve , If you have a mass air flow maybe needs to be cleaned . Distributor cap and rotor button can be going bad . Is there a way you can put up a video of the sound your hearing or feeling ?
I'm just saying those rarely go bad all it is , Is a valve suction one way not the other you can take that off and just suck on the end and blow to see if it is working . PVC valve should be rattling when you take that off if it is rattling slow or sticking that could do the same issues .