Have you checked the fuel pressure? These engines need about 60psi of pressure to start. Failed fuel pumps are ridiculously common on them, as well. How do I know that? I have had two Blazers and between them I have done three fuel pumps.
So start with the simple test. Simply lay under the truck or near to the tank as you can and have someone turn the key on, but not crank the engine. Listen for a humming sound. If you do not hear it, then the pump is not running for some reason or another (fuse, relay, or pump). If you hear it, but it is not a smooth hum, but more of a train wreck sound complete with grinding, bad pump.
If it sounds right, then you will need to get your hands on a fuel pressure tester. You can borrow one from Auto Zone/Advance Auto.
Here is a general how-to-guide.
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Sunday, February 18th, 2018 AT 7:05 PM