Running rich?

My car shoots carbon out of my exhaust at times. Along with this is the fact that it has new plugs and they are black at the tips after less than 500 or 800 miles. I'm wondering what would cause this to occur. I had the head re-done and replaced some other stuff on the car. Is timing the only thing that would cause this? or is there another culprit that it could be? please let me know if you know anything.

Drew

Oh yeah-the car is an 88 lude Si

i think your burning oil which means your piston rings are f@#k.....whens the last time you changed the internals of that bad boi?

I actually just had my head redone, replaced the head gasket, fixed the fuel injectors, put a new air intake on, and replaced some other stuff. It also seems to be leaking oil a little cuz there is a little bit of smoke coming up from the rear of the engine. you still think the pistons are fried? i just changed the timing on the car as well as the distributor timing. thanks

Drew

I'm throwing a guess here that it is a bad O2 sensor. Running lean for a prolonged period will damage your piston rings, and running rich for a long time will cause them to get "sooty" and eventual long term damage. Check your O2 sensor.

and timing