I have a 95 buick century with a 3.1l V6. It has been acting like it is starving for fuel so I figured that the fuel pump / fuel filter needed to be replaced. I installed a new fuel filter and the car did great for a several mile test run. I went to start it about an hour later and it started acting like it was running out of gas again. I pulled a fuel line loose and ran the fuel pump to make sure that the pump was running properly and verify that the gas was not compromised (debris / water) All was well so I reconnected the fuel line and pulled a plug wire to verify it was getting fire. When the car was started it ran a little rough (it was on 5 cyl) but when I reconnected the spark plug wire it acted as though there was a fuel problem again and died. This led me to believe there is an electrical problem. I traced down the ground from the fuel injection harness and cleaned it throughly and the car ran great for about 50 miles.....now it is doing the same thing. Any ideas?