Ni200 degradation, not happy seeing this.

[Mattj317]

Jefx, that light headed feeling could just be the result of the coughing fit itself. Oxygen levels in your body are altered by prolonged, forceful coughing, causing you to feel light headed for a few seconds.
A forceful cough can even alter your heartbeat. I've been advised by my doc when my heart is racing to try a few, forceful coughs to reset my heartbeat.

 

[TKS]

Do you have an adjustable 510 pin? I've noticed huge changes in Ohm reading ( sometimes as much as +/- .1 Ohm), resulting in a dry hit. The problem is resolved by adjusting my pin.

I've also noticed the same black chunks as you from time to time. No idea what it is. My coils and wick have been gunking up pretty quickly as well, like within a day.

Been using it on a VaporFlask with spring loaded 510

 

[TKS]

Using a VaporFlask with a spring loaded pin, never had any issues with consistency after ohm refinement. I been getting this gunk every RTA/rda I use it on. Happens with pre built kanger coils as well.