1992 Toyota Supra Turbo.Black smoke.......

[Joshakatiny]

Hi I am new to this site and was curious to know if you guys might be able to help me.I have a 92' Supra turbo that Is getting horrible gas mileage and smoking while accelerating.It is black smoke so i know its burning fuel way to rich,but i do not now what i need to replace.It will also stall if I hit the gas hard and let off .It also seems to be idling incorrectly.What causes this,or what could cause this?P.S. bad gas mileage means it cost me 100.00 dollars in gas to go 300-350 miles and gas is only 2.40/gallon.