98 Nissan Sentra fuel injector pigtail

I have tried to search the internet but can't seem to find it. The 3rd plug from the left is acting up. I had previously had a misfire in injector 4 and found out it wasn't working by using a screwdriver to listen for the clicking, so I replaced it and everything was running great for a while. Now it's having the exact same choking symptoms except it goes in an out randomly instead of being a steady rumble. It will idle super smooth for a few seconds, then start******** really bad, then back to idling smooth, etc. When I went to listen to the injectors, they are clicking fine, but when I bump the wire connected to the 3rd one I can reproduce the symptoms. It doesn't happen when I touch the other ones, only the 3rd. The connector itself is not loose, it just idles horribly when I move the wire a little. The service engine light is on during all of this.

Thank you for your help. I thought it seemed funny that the shop would say they can't get the part because I just knew that these connectors couldn't possibly be that proprietary. They did tell me that if I could find one for it, they would put it in but wouldn't guarantee the work, which is fine, I just don't have the equipment or skills to put it in myself. How would I go about finding out what the polarity is on the existing one? When I go to buy the new part, will it tell me the polarity in the item description?

I know this is really late but I forgot to come back and reply. I went to a couple of stores nearby and both said they didn't have what I needed, so I ended up pulling some off a vehicle in the junkyard. I got it spliced in without any problems and the issue has not returned. Thank you so much for the input, I appreciate it. :)