Why does my Jimmy dies every time I try to back.

Why does my Jimmy dies every time I try to back out of my driveway? Checked relay fuses. Put in a manufactured fuel pump in it a week ago.18 months ago they put in an after market fuel pump had to cut the orginal plug to fit the after market and we had to put back the orIginal plug splicing it and taping it to work for the one we put in keep in mind fuel pump is brand new out of box. Now two things either the chassity fuel filter could be plugged or there is a wire grounding out some where I need help figuring this out I do not have a book or DIAGRAM FOR A VORTEX ENGINE.V6 would appreciate helpful information.