Two problems

[Turbo-T Wannbe]

1. I've got a bad tip in stumble. It's not the chip as I've tried several, no pre-turbo exhaust leak, TPS and IAC set correctly. What are some other possible causes?

2. What does black smoke out the tail pipes on accel. mean? O2s are right around 800.

 

[ES1]

Is there someone you can trade out a MAF sensor? You also might try this:
Well, it looks like my tip in stumble may be cured thanks to another board member. He stated that his stumble was helped by turning his cam sensor ~ 1/8 turn counterclockwise from the factory spec. Yesterday I set the cam sensor to spec and it still stumbled, turned it 1/8th turn ccw and no more stumble, not even taking it out in the cold today.
Smoke turbo? Rings?