I have 5.3 showing p0306 code. Idles rough smooth out at road speed.

What is your question?

I've replaced spark plugs ,wires, cleaned mass air flow, checked for vacuum leaks, new o rings on injectors ,checked compression, vacuum, fuel pressure, all are within specs. Swapped injector and coil off good cylinder. New intake gaskets, checked fuel regulator for leaks and still get the p0306 code. Any help would be appreciated, I'm at my wits end