swb, 5speed, 5.0litre. running great, all of the sudden, a "backfire" maybe, burb? started sputtering, jumping, wanting to die. was told fuel pump on it's way out. replaced the pump on the frame rail hoping it was the issue. old one had good fluid flow(gravity) on the input, no output at all. now the new one??? hear it or... with key on till it meets psi set point, no crank. fixing to check output, maybe input too. any suggestions?