Sure. I have a theory. It happened to me recently.
I had one injector drooling after shutdown. Pooled fuel in my LIM. Caused my PCM to think I was running rich, and it leaned out all the injectors. I either fixed it, or it went away on it'* own.
If you have a drooling injector, this can happen to you. Pull your fuel rail, and put a small container under each injector. Prime the fuel pump, and go drink a six-pack. Come back and see if any are drooling. Granted, I KNOW you have recently rebuilt and flow-matched injectors, because I helped do them, but you can't account for anything that was in there and too large to pass through the orifice, or anything that was in your fuel rail when you installed them. It'* something to check. It also wouldn't hurt to 'read' your plugs and O2 sensor at the same time.