1.3 bar bog

[Sachelle Babbar <sbabbar@iris.nyit.edu>]

N MY 84 5ksT i have a problem that has been bugging me for a while. When
it's cold out and I FIRST START THE CAR and get up to full boost (I don't
do that), it runs fine. Once it warms a little (not fully) I'LL be fine up
to 1.2 bar then at 1.3 it suddenly bogs. I think once someone told me of
black smoke out the back. Once I saw it. When it warms up fully, there is
no problem whatsoever to my max (1.8). I'll shut the car off for maybe 5
minutes and the problem is back, but goes away after a mile or two. What
does this sound like. My o2 sensor was changed (with one with lower miles
on it), that did change the effect of the bog slightly, but it was still
there. I didn't use a new o2 sensor because i didn't want to ruin it with
the excessively rich mixture. Can it be the o2 sensor? What does it sound
like?Thanks....Steve