GM-GMC: smoking 4.6, unburned fuel, inverters

Question
I have a 2001 4x4 with a 4.6 and lately the check engine light has been flashing and it has been putting out black smoke.I recently removed the caty-inverters because someone said that was the problem but it is still doing the same thing..A friend said it was borning too lean ,it doesnt do it all the time just every now and then..When it does it gets hard on gas and almost seems like its flooding

Answer
A flashing MIL indicates a major misfire and the black smoke kinda confirms it, especially with no cat's.  The unburned fuel would just go out the pipe.  I would recommend getting a scanner and find out about the misfire or take it to a garage with a good scanner and have it looked at asap, it can do some damage if left unchecked.
Hope this helps