code P1443

Hey my check engine light came on and apparently the code p1443 is a evap emissions control purge valve. Do any of you all know what this is? I think its a sensor loced beneath the air filter but im not positive. I have had some problems with a rough idle, could this cause it? I'll have to check it in the morning with the digital voltometer, but the chiltons guide doesnt explain it very clearly. There are several other sensors with similar names. I just don't wanna get stuck buying sensors I dont need. Any help would be great.

It's a valve between the charcoal cannister and intake manifold. It opens to allow vacumm to suck gasoline vapor from the cannister into the engine. I don't know if it stays open or not. I think a bad or loose gas cap will cause the same thing to happen.