The vapor starts strong with a new atty but over a week seems to fade, and the atty gets hot quicker as well(maybe two puffs) before no mas.
Sounds like possibly the juice you are using. I use a 401, and my attys generally last about a month or more depending on fluid. I have similar issues with the vapor fading and heat, but over a longer period of time. But I've found that darker fluids cause this to happen much faster than lighter colored fluids. I mix my own using Bickfords flavors, and cola (which is almost black) will kill my atty in two weeks, whereas rum or pineapple (clear) will allow the atty to last almost two months before a serious drop-off.
My theory is that whatever causes the coloring is leaving deposits not only on the coil, but in the wick itself, so that further fluid is unable to wick properly. After using a darker fluid, I've tried doing a burn-off with a manual battery, and I can see the coil getting red hot, but no Vapor. It just affirms that some how the wick is getting clogged, and no amount of flushing, cleaning, or soaking seems to fix it..
Anyhow, again if you are using a darker colored flavor, that could be it.
HTH