Been dealing with this exact problem on my setup. Kanger subtank mini with a KBox, and 0.5 ohm coil.
Symptoms:
- Ohm reading bounces all over the place, up to 9.9 (often stabilizes at 9.9 and starts flashing)
- Turning the air flow ring causes the ohm reading to jump around
- Pressing the KBox and the tank together drops the ohm reading to 0.6 or 0.7
- Putting side pressure on the tank drops the ohm reading to 0.6 or 0.7
As someone else here stated, the base unit might not be screwed completely together. Using adjustable pliers and a vise grip, I was able to grip the grooved ring (below the airflow ring) and the VERY tiny metal lip above the airflow ring, and tighten these. These only tightened about 1/8 of a turn (perhaps even less), but now the ohm reading has stabilized at EXACTLY 0.5 ohms, and doesn't deviate.
I'm guessing some base units weren't assembled to the proper tolerances at the factory. See the attached image for the two areas you'll need to grip and tighten (arrows indicate the two rings to tighten). Unfortunately tightening these will almost certainly result in stripping off some of the anodizing. My black tank now has some very obvious areas where plain steel is showing. Might be able to mitigate this by wrapping your tools with some electrical tape, but I wasn't concerned as my tank is already a bit banged up from being dropped.