strange shuddering

[tmb]

hey all, first post here.  just got my 89 200TQA
back from my buddy eddy (another audifans
member).

while driving home last night, i noticed some odd
shuddering while my foot was on the gas.  i
wasn't accelerating at the time, tho.  just sorta
holding my speed in second at about 30km/h. 
initially, i wasn't even sure that i was feeling
it.  when i looked at the tach and speedo, there
was nothing being registered, but there was most
definitely something amiss.

has anyone had anything like this happen to them
before?

another strange thing i noticed was that if i rev
it out thru the gears, it feels like its being
choked until about 5500, at which point it
hunkers down a bit and accelerates a bit harder. 
the boost guage displays 1.2BAR until 5500, where
it peaks at 1.3BAR.

i'm thinking possible O2 sensor issue, or some
other electrical sensor not doing its job, but
it's pure speculation at this point.

the t-stat is not working, so maybe i'l do that
first before i spend any time/money on anything
else.  oh, and anyone that says i shouldn't be
revving that high on a cold motor, you're right. 
i had it idling for about 10 minutes before i got
on it.  after idling that long, the coolant/oil
temps were definitely up to spec.

in case this helps, the car was 210Kkm on it, but
it's got a freshly reconditioned head that has
less than 100km on it.

thanks so much for your attention.  i look
forward to a long and exciting time with this car
and this list.

jason
tmb

__________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com