[Blue Bowtie]

Is the idle RPM normal, but just rough?

If so, all the usual suspects would apply - Ignition system, fuel delivery, and compression. Spark plugs, wires, distributor cap and rotor, injectors, sticking or leaking valves, a sticking/leaking EGR valve, incorrect PCV flow, etcetera.

Start with the easy items, like spark plugs. Even if they are not the cause, they usually act as a reasonably good barometer of how each cylinder is firing, so pay attention to where each plug was located.