Selected P Cygni profiles of the CSPNe showing FUSE variability. For each line, the top panel shows the averaged spectrum and the lower panel the temporal variation spectrum, TVS; both are normalized by the continuum level at the spectral range of the line. Note that we have omitted the TVS at specific wavelength ranges where the continuum level of the averaged spectrum falls to zero, either in the trough of some lines (e.g., the S vi λ933.4 Å line of Sp 3) or at the location of narrow, deep absorption lines (e.g., the P v λ1118 Å line of IC 2149).