2001 Chevrolet Blazer won’t start

Car stop due to low oil pressure when oil level was top off engine started. After about 1/2 hr engine would turn over but would not start. what are possible problems?

The list of possible problems is endless given your description. Is the check engine light on and what are the codes?

A bad crankshaft position sensor would be at the top of my list.

https://www.rockauto.com/en/catalog/chevrolet,2001,blazer,4.3l+v6,1371440,ignition,crankshaft+position+sensor,7196

Tester