So i've checked everything but my fuel pump and fuel filter, and my idle still revs and drops revs and drops, what are the possibilites of it being the fuel pump..?? My rendition of it was, I didnt know if a fuel pump could eventually start dying and eventually shut off, or does it just stop working all at once..?? Are there any vacuum lines that maybe I didnt check..?? thanks..

JDM D15B - 94 dx coupe