Nope, it is for Hot-start purposes. It bumps up the fuel pressure to help start the engine back up when it is warm. It has something to do with gas vapors that build up in the lines, fuel rail, etc., that can in theory make a hot-start difficult. By bumping up the fuel pressure temporarily, the fresh flood of gas through the lines washes the vapors through. It was a good theory on Mitsubishi's part, but not entirely necessary.
It can easily and safely be eliminated. I have eliminated mine on all DSM's and my GVR4 with no ill effects really, other than the occasional sputter/misfire for several seconds only if I let the car sit for exactly 20-minutes or so on a warm day and go back and start it. I can only attribute it to eliminating the FPS, but no big deal, and so very occasional, I could care less.