Sounds like you are losing fuel pressure. Check your fuel pressure when it is not cranking. The pump may be coming on but not building up pressure. Check on the link on the left side of the screen First Things to Check and see how to read and check fuel pressure.
Fuel pressure specs
2.2L 41-47 psi
4.3L vin Z 9-13psi
4.3L vin W 55-61psi
Wednesday, August 21st, 2013 AT 6:41 AM