p0341 DTC on 02' alero

2002 alero, 3.4l engine. Sisters car, started 'missing' at certain speeds, running a bit rough. Got a p0341 camshaft position sensor A circuit Range/performance (bank 1 or single sensor) This pretty much mean I need to replace the cam position sensor? Is there more than one sensor? I am clueless as to where these things are located, if anyone has any input even though this isnt an alero forum thanks in advance...