i have a 91 z28 and it has a rough start problem. when i crank the motor over, it cranks for a few seconds until the motor does fire but slowly. then after continuing cranking it will fire up.

 

Could be many things. Check your battery voltage first. So its a slow start from your description after its warmed up and then shut off does it fire right back up? Could be fuel pump, starter, battery, compression, plugs, wires, all sorts of things.

 

Sorry i wasn't entirely clear

I replaced nearly everything fuel related. (pump, filter, regulator, relay). i put in new plugs and wires. it cranks over fine, its just it seems to hesitate to fire. but when it has been running, it starts fine

 

and injectors too.