hard starting

when I start my car cold sometimes it will run for a few sec then shut off, if I start it again it will start right up. usually it only does this after it sat overnight. when I start it warm I have to crank it a long time to get it started but if it sits about 5-6 hours It will usually start right up. does anyone know what would cause this? my car is an 87 trans am 305 4bbl

it sound like fuel, check to see that you are getting enuf fuel, if not start with the basics, fuel filter, but it sounds like a fuel pump, if you replace the pump, be SHURE to replace the fuel filter at the same time, other wise you take a chance of the pump going out again.