I had the same problem at first. A bit of tweaking and I had it working well (Igo-W). I found my problem was a combination of things. First of all I was really bad at building coils initially (even now I'm not an expert or anything, but I get 'er done) and my coils had hot spots. It's easy to tell if this is a problem. After checking the resistance, but before wicking, slap that sucker on your mod and fire away. Your coils should heat from the center outward, and should glow evenly. If a couple loops on the exterior blaze bright, but your center loops are dull, that's a problem. You can fix it; I use tweezers to squish my coil together and then redistribute the loops when my coils aren't glowing like they should. Caution, make sure you recheck the resistance any time you fiddle with the coils.
Second, I was using a juice that was too high a mg. I had been vaping 12 mg before starting to rebuild. The employee who set me up with my new gear warned me to lower my nic with the rebuildable, but I figured it would be fine, especially if I wasn't venturing too low into subohms. I was wrong. It was really harsh. Even at like .9. So if you're using anything higher than 6 mg, drop your level. It'll help.
Last, I was flooding my atty! Too much juice in the device and I ended up with a really heavy, idk...mist? Instead of actual vapor. My coil was just spitting fine particles juice into my throat. Less juice and problem solved.
I'll also say that the airflow with the Igo-W at least isn't the greatest. If you're into it, drill it out. You can also buy them drilled out, which is what I'm going to get around to doing eventually.
