Fuel pressure prime
 

98 camaro 3.8 replaced fuel pump just the pump not the sender...
It will start perfectly but after it sets for 3-4 hours or over night it takes forever to start like there is no fuel coming to the engine. Any suggestions? Also one more issue...this was happening before the fuel pump went out...so when your doing 60+ mph and you floor it to pass someone it looses all power and acts like its misfiring but there is no check engine light on. Just no power what so ever when you floor it just like you cut the air off.
I would appreciate anyones comments

Assuming that the fuel pump is good, since you replaced it, then the hard start may be an indication that the fuel pressure is not holding when the pump is off. You need to test the fuel pressure with a proper gage, which you should have done before going for the fuel pump gusto. There could be a bad fuel pressure regulator, a leaking injector, or an actual fuel leak. Loss of power under load, as you described, could be due to insufficient fuel delivery, which could be caused by a bad regulator, clogged fuel filter. A clogged cat would also show similar symptoms, as would the need for new wires and plugs. It could also mean the new pump is bad.

I just had my fuel pressure regulator replaced and those are the EXACT symptoms my car is having. Everyone I talked to said that either its the fuel pump or my car isn't holding the proper pressure and considering you just replaced the pump, I would say its time to shoot for a new regulator.