I have/had the same ??bucking? problem on my 99 SVT. I too recently changed the plugs, wires, and preformed a few other small fixes but to no avail. While it may be a matter of coincidence, I disconnected my stereo system and all is well. When I reconnect the stereo the intermittent stalling comes back. The fuel pressure remains fairly consistent even when it stalls out (this is one of the first potential problems that came to my mind). Please let us know if the new pump is the right fix.

white svt/ 2 tone leath, eibach, scroth, lunar, vortech can suck my spline driven shaft