It is possible to get a bad rebuilt injector, and the chances of you unfortunately putting it right into #1 where you had the problem before are not astronomical - 20%?
So the cheap thing to do as a test is swap the injector from #1 with another injector already in the vehicle, say, #2 or #3 or whatever is easiest to get to.
In doing that you fairly conclusively eliminate an injector as the problem.
On the other hand, for all I know, your car is doing on one cylinder what mine does on all five.
Ken300D