1997 5.7 vortec express Starting?!?!?

Here we go, It starts normal sometimes. Sometimes you turn the key to start and get a LOUD grinding metalic noise-no start. Cycle key and restart and starts and runs as it should. Cold or hot same issue, sometimes starts and runs fine and other start attempts sounds like a loud metal chatter. When it runs no power loss, or bad idling. No ses lights.

Sounds like the bendix gear on the starter is not engaging fully and what you are hearing is the gears spinning and trying to engage the flywheel teeth. Eventually the gear on the starter will go bad and you will need to replace the starter or rebuild the Bendix drive.