3.8 running rich

[hihosilver]

Hi Mustang Experts,

I have a problem with my 2000 3.8 litre stang convertible. At start up the vehicles struggles, as if it was getting too much/not enough fuel/air mixture. This vehicle runs rich and exhibits black soot out the tail pipe, even after long highway drives. The car also sputters as if it where struggling when quickly giving it a shot of gas (in cold temperatures)

on the accelerator pedal. If anyone is experiencing or has experienced similar problems, please let me know a.s.a.p. My dealership tested the car once and could not find a problem. The vechile stumbles in cold temperatures. But the car always exudes black soot inside and around the tail pipe. Keep all four on the ground!