It doesn't fluctuate when in use but sometimes if i leave it for a while then fire it again, it might jump to a higher ohm then if i leave it again and fire another time it will be the first ohm reading. Edit: like right now im using the same coil as last night reading at .36, right now its reading .39. Edit 2: well then lol, took a hit and the coil snapped (from a short maybe), it was working fine for the pass two days though -.- Edit 3: I put in a pre-built coil at 1.8ohm, but the device reads 2.02ish but its jumping up and down from there so i guess it is a bad connection. Mod surgery time