dieseldude,
To adjust the mixture a 3mm allen is needed in the hole in the center of the air filter. But trust me this is not the best way to approach the problem as you need to do any adjustment with an understanding of duty cycle and eha readings. The problems you have described are not indicative of a fuel problem yet. I would still pull your plugs whether you put them in or not they will tell a story. I believe you may actually have an ignition problem rather than a fuel problem. If it is only under load from a complete stop that you see it and the idle is rough like it has a dead miss, I am very suspisious of your ignition. First thing to do is to get your fuel mixture tested. You can do this by checking your duty cycle and eha readings. If all is well then get the emission gases checked if they are good then I would recommend checking your ignition next. None of this should cost a fortune if you can find a shop that does diagnostics rather than fixing by replacement.
m

__________________
Martin Ingram
Colorado Springs
2005 320 CDI
2006.5 VW Jetta TDI
1991 560SEL (179000 Sold)
1972 280SEL 4.5 ('The Lead Sled' 320000 miles when sold.)
1972 220D (225000 when sold)