If you can't get to it from above, there is a chance the debris is lodged in or near the cabin air filter housing, which would make it much easier to get to. (mechanics.stackexchange.com)
Typical sources of unmetered air include disconnected vacuum lines, perished hoses that have holes or cracks in them, compromised intake manifold gaskets and cracked air filter housings. (mechanics.stackexchange.com)
The purge control valve on your vehicle should be behind the engine air filter housing. (yourmechanic.com)