typically a tightening draw signals that your coils are gunked up and its just time for a change.
If your coils are neither gunked up or burnt, it may be a airflow issue.
Are you using that specific t3 on 1 specific device? The device's center post/connection could be to blame.
Or the air holes in the actual t3 could be blocked for some reason. Perhaps
juice got into them. Clear them out.
I find that my t3 gets flooded quite often if A. It is running low on
juice, or B. I took too hard of draws.
Both of these can produce a tighter draw from flooding. You want to tip the t3 upside down and inhale.
Tipping the t3 upside down and inhaling (when it is flooded) ....
allows the excess juice in the coil chamber to vaporize.
(while also preventing more juice from entering the coil chamber)
Another reason for the tight draw could be the wick. The wick may be too large for the wick holes. You can easily thin out the wick by pulling small pieces of it out through it's holes. I do this on all my CE style tanks. Hopefully 1 of these tips will help ya outtt.