idle and fuel problem

[Craigthenormal]

Ever seince i have gotten the car it ahs had a bad idle, in park it is at 1500 rpm, then put it into drive and the rpm drops to about 900 or so, if it idles for more then 10 seconds, it starts to bog down and lots of black smoke out the tail pipe and stalls. the car is a 91 talon fwd turbo auto,completly stock except for the mbc,boostg gauge,and 2.5" downpipe with test tube. When it shifts at higher rpms a dark smoke comes out, it looks to me like black, but my friend driving behing me says blue. i dont know if the two problems are related.

 

[Craigthenormal]

ohh yeah forgot to mention. i'm getting about 14 mpg... is that right?

 

[DevilSperm]

get a logger...sounds like its running rich..i was also once told that if a car smokes between shifts, its rings