[W126 Coupe] vacuum leak question

[Shayegan, Richard]

I finally got around to fixing the vacuum leak at my number 8 injector (the mechanic who had replaced that one a while back while diagnosing the fuel distributor apparently put a new o-ring in without taking the old one out, which caused the leak), but I remember someone saying that a way to test the vacuum is to turn on the A/C at idle. Well I tried that before and after, and while the movement of the economy gauge when I do this is a LOT less now than before, the economy gauge still goes slightly off the peg when I turn on the A/C at idle. Does this indicate that I still have a small vacuum leak somewhere, or is that just how it is?
Thanks,
Richard