I'm not sure if your problem is related to mine but I'll let you know what happened with mine because I'm sure you'll run into it sooner or later.
I have a v2 vamo. I had only been using vision tanks and had never had a problem. Recently I got a Kanger pro tank and was having trouble getting the vamo to fire it. Here's my original thread.
N that thread proteus pointed me to the vamo center pin problems where the pin gets depressed and won't make a solid connection with the tank. That was happening to me. Sometimes the vamo would read the Kanger as 2.2 ohms and sometimes as high as 5 ohms. I was running the vamo in VW mode and burned out a couple of the Kanger coils pretty quickly.
Anyway, I fixed the center pin problem and no longer get the random ohm readings. Here's a really long thread with several ways you can fix it. This seems to be fairly common on the Vamo but it's an easy fix. http://www.e-cigarette-forum.com/forum/vamo/375871-vamo-ohm-error-fix.html