fule pump problem 96 seville

I have a 1996 Cadillac Seville SLS, problem started with the fuel pump failure, the pump was visually broken, I ordered new fuel pump (Delphi) from web and installed it along with new A.C. Delco fuel filter and fuel pressure regulator. Car started up no problem then during driving it started to run erratically once I shut it down it ran fine it happened 3 times, I replaced MAP & TPS sensors. The lines might have had air in them and needed to be purged. The car then started to blow the fuel pump fuse (20 Amps) after 20 minutes or so of driving I researched the service manual and replaced the oil switch sensor and relay, I checked positive circuit to pump connector before tank and fuse block with no grounds shorts detected, it still blows fuses after driving about 15 to 20 minutes and after replacing fuse on road the time span shortens, I’m beginning to think it’s a faulty new pump or small harness from back of tank to pump, the car only has 69, 000 miles I hate to junk it for a minor fault…..I need some help to possible causes for this vehicle….Thank You