Okay I believe I fixed it. I unplugged all the injectors, filed the corrosion off of the one that was giving trouble, sprayed them all with lithium grease, and fixed some wiring that looked questionable. Now it runs like a dream, no stumbling at idle, no more missfiring, better throttle response, and I can't replicate the misfiring problem like I used to be able to so I'm gunna call that fixed.