running too rich

3.2 L running all kinds of rich. i took it to my mechanic, and he has had it for two weeks now, and is telling me he cannot figure out why i am running so rich. i'm blowing black smoke, have to feather the pedal to accelerate, check engine light comes on after about 3 minutes of driving, idles rough. does anyone have any suggestions?

Have the O2 sensors been checked?

What kind of codes is the computer throwing out?

Two weeks to diagnose the problem? Maybe you need a new mechanic.

The black smoke on my Rodeo was caused by a bad O2 sensor:

http://www.automotiveforums.com/vbulletin/showthread.php?t=258045

A leaking fuel pressure regulator will make the engine run rich as well.

I agree with RF, the codes should tell the story.

Post again when the trouble is found.

Dale