Have a 1998 blazer 4.3 engine has spark but will not fire?

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.