Pontiac Repair: need help!!!, fuse boxes, grand prix 3

Question
I have a 1991 Grand Prix 3.1 engine and every time i start it up it dies as soon as it starts. I have replaced plugs, plug wires, fuel filter,checked the fuel relay,fuel pump is good. So what could be the problem? Write me back ASAP so i can get it fixed.                 Thanks
                          Shawn

Answer
ok well first things first if it has a security sysytem that might be the problem,, not ok lets look does it have spark when it starts and continues? ok if it has spark lets look at the fuel system,, does the fuel pump run in the run mode? we have to forst detemine if it is spark and or fuel that is stalling it, we need to have a fuel presure test done and a spark teste while it starts and dies also check all fuse boxes for blown or loose fusues