1989 IROC Camaro Hard Starting/Cold Starting

I have an 89 Iroc Z28 Camaro with with a 5.7 TPI, and it has hard start issues on an everyday basis. After sitting overnight, the car will just crank and not turn over. However, Cold Start fluid sprayed into the intake will correct this, and the car will start right up. If I drive around town and stop somewhere, then come back to start it, it will start right up. Numerous mechanics have looked at this problem and cannot figure it out. The tank was recently pulled and cleaned and the fuel pump replaced, and this had no effect whatsoever. Whenever I turn the ignition, I can hear the fuel pump turn on and the sound lasts about 2 seconds. This problem has been such a nuisance over the years, and any insight would be greatly appreciated.