CIS mixture adjustment access hole?

[glen powell <gpowell@acacianet.com>]

This adj access hole is empty on my ur-q.
Should there be a plug in this hole?
Will a missing plug here result in a vacuum leak?
There is no observable problem that I am aware of,  just curious.

-glen

It's running rich, and it's an easy if very delicate adjustment.  Get the 
engine hot and idling with a CO meter probe up its bum, and use a _LONG_ 3mm 
Allen key down the hole between the air mass sensor plenum chamber and the fuel 
distributor.  Don't make the mistake I did and walk into a tool shop asking for 
a long 3mm Allen driver - ask for a Bosch fuel injection adjusting tool.  
 <snip>