[16v] o2 sensor oddity?

[joshhignight@techography.net (joshhignight@techography.net)]

So I've been running my mystery Ford o2 sensor for a couple weeks=
 now, and it's been running a LOT better. Fuel mileage is better,=
 although still off par from what it used to be. 

I got my A/F gauge reading again, and I noticed that this thing=
 is now reading rather slow. I've also noticed that pushing the=
 enrichment switch on the throttle body while the car is idling=
 does absolutely nothing. Yet when I goose it I get a nice little=
 puff of black smoke on the top end (I don't get that puff if I=
 stop short of the enrichment switch). So what gives?

Thanks,
Joshua