HELP...mixture too rich...
 

I'm trying to chase down a problem that's keeping my AF mixture too rich and have a question for the group:

What does the velocity stack in the air box do? I have a 2001 Golf 2.0L. I think I'm suppose to have one, but I dont see it. Maybe it was taken out by the grease monkey that changed my air filter? Could the lack of one of these be my mystery?

Thanks!