misfiring code P0303

[qman]

Good afternoon everyone,
I have a 2015 GMC yukon denali with a 6.2 L engine that has a misfiring code on the number 3 cylinder. I have checked for spark from the spark plug and the coil, I found no problem, so I replaced the spark plugs, coil, and wires anyway, misfire still is still happening, then I went to the injectors and replaced them and the fuel rail, (do I need to say why I replaced the fuel rail). Anyway I still have the misfire, any thoughts and help would be appreciated, I only use GM AC Delco parts. Thanks.