Just fixed this problem on a 1990 4.3. The pickup coil inside the distributor was bad. No signal was sent to computer to fire injectors. Make sure distributor is grounded well and if there is corrosion visible inside distributor save time and frustration by just replacing the distributor. I found several new ones on eBay for under $100. Had spark enough to run on starting fluid or if I poured gas in the throttle body but the injectors had no signal if checked with NOID light.
Check your coil pack or the spark plugs.
If you have spark at the spark plug, it is probably a bad fuel injector.
Spark plugs not producing enough spark. Battery doesn't have enough charge. Old fuel.
Yes, sometimes a faulty ignition switch can cause the engine to not fire. Also, a bad spark park can the engine to not fire.
Try your spark plugs and wires first. I that doesnt fix it then check your coil pack/s
Your engine timing is off.
replace the spark plug wires
Does it have spark?, Compression? Timing?
Standing in the front of engine, it will be on the left rear side of the engine. Back by the fire wall.
You could have a problem with a vacuum line.
what is the diagram for a 4.3 Chevy blazer 1998 and the firing order vehicle is fuel injected
The spark travels from the coil to the distributor then from the distributor to the plugs. So if you have spark going into the distributor but not coming out to the plugs, I would blame the distributor cap and rotor being at fault.