Hello and Welcome.
My name is MIKE - Im happy to help / advise.
Air intake as such will not cause this issue -not being blocked - but what can cause it is unmetered air going into the engine - ie, a leak.
You need to check very carefully all the vac / air pipes on the engine...looking for loose pipes / fittings - and splits / perished pipes anywhere - Anything like this will cause this.
Also check the TB - throttle body - its mount / gasket - see if the whole unit is tight as it should be -
Use a length of hose as stethoscope - to listed for air sucking...
All your symptoms point to this.
If all else fails- you could well have a faulty air mass meter - but do check as above first before any parts replacements.
Let me know how you go..and / or let me know if you need anything further on this..~>>~~>>~ Meanwhile now at this point- Please do click on the "Exc / Ok rating" for me at this time.. "Thank you" in advance for that ... Note that you can get back to me anytime at all after doing the rating - it doesn't close you out -- Best Rgds, MIKE