Just to be clear, are you talking about the "EVOD Kit" or the "EVOD Clearomizer"? There's a difference...the "kits" usually come with a relatively inexpensive, lower quality clearomizer. The clearomizer is a unit that looks like anodized aluminum with two clear stripes to allow you to see the liquid. If it's the former, I probably wouldn't mess around any further.
If it's the latter, it kind of maybe sounds like you have an incorrect coil or maybe just a lower quality one. I find them fairly reliable, but do occasionally get gurgling. (I just put a paper towel on the tip and shake forward a couple times to clear it.) There's a lot of cheap coils on the market, I've found the actual Kangers work the best. Also, the coil has to be fairly snug...I've had a couple times where the bottom will unscrew, but the coil won't...it's an annoyance, but it's easy to pull the coil and put it back on the base. You just have to be careful about what's where so you don't leak when unscrewing. Also, make sure that you've established a regular, thorough cleaning cycle...I usually do it upon changing coils or fluids. A good long soak is important to keep the threads free of gunk. Personally, I use cheap vodka for a 3-24 hour soak on my clearomizers and Everclear on my coils. There's a lot of other things that work, too. Water isn't enough (for me) to really clear that old flavor out, especially if it's a strong one.
I think my favorite clearomizer so far has been the mini-pro tank. I have a bunch of the EVOD's, but that mini-pro is super satisfying to me. I like the EVOD's for sampling, but my "all-day" is a mini and regular pro tank. I haven't tried every one under the sun, though, so my experience is limited.
Good luck!