I have a Glock 17 too but generation 5 so I can't say that the parts in question are the same or not. I had the same problem and went at it for hours to try to figure out why my trigger would not reset all the time. Excuse me for not being an expert and not knowing the names of the parts exactly but I was able to find out exactly what the problem was.
I changed the striker spring, safety plunger spring, and connector with aftermarket parts. The problem was in the lower assembly of the pistol and not the slide after changing the parts to aftermarket and back many times in order to figure out where the problem was coming from. The solution was not anywhere I can find online on any tutorial.
The area to look at is in the trigger housing towards the rear where you find the connector and metal part shaped like a crucifix. There is a little metal hinge that latches onto the crucifix that is located within the plastic housing in the rear. The function of this mechanism is to provide enough forward pressure of the trigger to allow the pistol to cycle properly.
Once I found and latched this springed hinge onto the crucifix, it worked like a charm. It is not enough to angle the part in and out of the rear trigger housing but you also need to latch that part into the hinge that provides forward pressure to the trigger to allow it to catch the striker while the gun cycles. I hope this helps.
