Engine starts and goes dead immediately, will restart and runs perfect

The most common cause of stalling right after starting is fuel pressure that has bled down. That is typically caused by a leaking injector. The fuel that leaks into the intake manifold will sit there and that's what the engine initially runs on, but it stalls before the pump has time to build the pressure back up.

The pressure can also leak down through the fuel pump's check valve or the fuel pressure regulator. Those will cause a long crank time before the engine starts. None of those conditions are serious. To verify if low fuel pressure is the cause, turn the ignition switch to "run" but don't crank the engine. Wait a couple of seconds, turn it back off, turn it back to "run", wait a second or two, then crank the engine. The fuel pump will run for about one second each time you turn on the ignition switch. That will give it extra time to build pressure.