I have a 1998 Chevy blazer RWD. I recently replace the engine and it ran perfect. No problems. Then suddenly I started having a no spark issue. My fuel gauge starts to read empty and after a few tries of starting. The security light comes on but doesn’t blink. Then goes away after I turn the key off. I have replaced the ICM, Coil, CKP and fuses. My issue is the it seems that the ICM is not sending it’s signal to the coil. I did get the truck to fire up randomly by messing with the ground wires on the back of the cylinder head. All components are getting power to them. And the crank sensor is sending out it’s pulsing signal. Has anyone had this happen or can lead me in the way to fuel wiring diagrams to figure out why I have no spark. Again. This is an intermittent problem.