Just peeked in the archives about this. The proper term is "throttle body".
About 60 hits."Throttle shaft" gets two hits.  A new TB from VW costs $565,
as of 2001.Got your attention now,I bet.

 The problems with these are two fold. First, the shaft being out of plum
from worn bushings can cause a sticking of the butterfly valve and
a "scratching" of the bore.The fix for the grooves this makes is good ole
JB weld in the scratches of the bore.I dont have these scratches , I dont
think,but I will now check real close.

The reason for the out of plum is worn bushings. I can see how to get to
them. Just remove the 2 torx fasteners on the butterfly valve and the shaft
slides out.The bushings look like fuel injector o-rings(but they are not
not not).I assume the bushings can be pryed out and new ones tapped in.

Has anyone done this? Cant fine this in the archives. Worn bushings cause
rough idle because the air is not precisely measured anymore(list theory).I
also think it can cause my problem of not clicking off the computer at idle
because the shaft is cockeyed ever so slightly.After all, the correct
throttle switch adjustment is just .002-.004.Dont take much  shaft tilting
to change this setting.  Can you say emmission testing problems? Any idea
where new bushings can be had? How about a carburator shop? I think the
bushings are not the same though.Maybe VW has them? Once again, I have this
problem on both TB's that I own. One has only 62K.The other ,about
170K.Thanks,Roger.