P303 Code 1999 Grand prix GTP?

I'm having an issue with the P303 code I know it is the misfire in cylinder 3. here's the scoop. I have replaced wires, plugs twice, ICM, Switched around the Coils (still resulted in cylinder 3) and finally the fuel filter. It only seems to stall and set the code at WOT at about 4-6k rpm otherwise it seems to drive and idle fine. does this sound like a bad fuel injector?