The coil may be the thing. I use the same tank over and over and I never clean the coil. The coil is maybe 3 weeks old. I keep reading about this dry burn thing. I tried it on the Aspire coils I had a while back and burned two of them so now I'm too afraid to try it again. I hate wasting money. I know, coils are cheap, but I guess I am cheaper. Lol.
I really think you need to change the coil. The coils are still cheaper than a pack of smokes.

I
think the dry burn is for people who drip. I don't think it works on coils for tanks like yours and mine.
It does, but it takes some practice. I use Kanger mini T3's, and generally don't bother with dry-burning or rewicking. If you look around, you can get the coil replacements for around $1.25, so it's generally not worth the trouble. If you want to give it a try, here's what you need to do. Take the coil off the battery, and take the tank off the coil, but leave it on the base. Gently rock the post out of it's seat. At this point, you will see the wicks. Remove the loose flavor wicks. They are cotton and will burn when you dry-burn the coils. The wicks that go through the middle of the coil are silicone and will not burn. OK, so rinse the wick and coil as well as you can. If you don't see a bunch of blackened junk on them, then you don't need to dry-burn, and can just put it all back together. If you do, blot the wicks dry as best you can, and put the base and coil on your battery (without the tank). Pulse the battery on for a few seconds at a time. You should start to see smoke. Keep pulsing the battery and eventually the wicks will dry enough that the coils will start to glow red. Do that for a bit, until it looks like the wicks are getting white again and all the gunk has burned off the coils. If you pulse it on for too long, you risk the coil popping/breaking, and then the head is toast, unless you want to recoil (whole other process!). Take the base and coil head off the battery, and rinse it thoroughly. If you can re-use the flavor wicks, put them back on. If they are blackened or otherwise un-usable, you can replace them with 100% cotton threads or cotton pulled from a cotton ball and trimmed to size. Put the post back on, and you are good to go!
(Again, this is why I mostly just throw out the old coil head and put a new one in. A lot of trouble, but it does work!)