The "Purge Control Solenoid Valve" is the "Purge Control Valve".
Rough idle is a typical symptom of something amiss with the purge control portion of the evaporative emissions system. It could be the valve itself is not operating correctly, the evap canister (vapor canister) may be leaking, or full of raw gas instead of vapor, or maybe even the purge control valve is getting a faulty signal from the ECU.
The soleniod is checked by applying a voltage to it and checking to see if it closes, or opens (I'm not sure if its un-energized state is normally open, or normally closed). If the valve is bad it is a no-brainer to replace.
The vapor canister can be removed and checked to see if it is full of raw gas (not supposed to be), but checking it for leaks is a bit involved, and probably requires equipmet not normally owned by a home mechanic. Vapor canister failure on cars with a lot of miles is common. Replacement is the fix.
Of course if the ECU is not sending a purge signal to the valve correctly, figuring out why may proove difficult, and possibilities could even include a faulty ECU. I expect this is unlikely though.