Keeps reading cylinder 3 misfire

Swap the injector with one from a different cylinder to see if the misfire goes to that other cylinder. Chrysler has extremely little trouble with injectors but if you changed everything in the ignition circuit, that just leaves fuel and compression.

I worked for a very nice family-owned Chrysler dealership for nine years, and one of the few things I never did was replace an injector. What I CAN tell you is there will be a few nuts or bolts to remove to allow the fuel rail to be lifted up. The injectors will either come out with the rail with clips holding them on, or the rail will lift off, then you pull each injector out individually. They have rubber o-rings on both ends. From what I can recall, I'm pretty sure the injectors pull out with the rail, then you slide a clip off to allow one to be pulled out of the rail.

You might consider performing a compression test first because Chrysler injectors do have such a low failure rate. The exception might be if the fuel system cleaner dislodged something that stuck in the injector's valve. They have very tiny screens built in to prevent that but I supposed it could get plugged. You shouldn't need to add any type of fuel system cleaner. Even cheap gas has so many such additives already. My '88 Grand Caravan with over 380,000 miles has been all over the country and has never had a fuel system problem. I always buy the cheapest stuff that will burn.