1990 Chevrolet S10 Blazer Question: 1990 s10 4.3 has spark, gas and timing is correct, turns over but it won't start

Fire to spark plugs is not sufficient, pull coil wire off dist cap insert phillips screwdriver (with a good handle) into wire hold shank 1/2 " away
from a metal ground spark should jump this gap with engine cranking, does it? If so do the same thing with a couple of the plug wires. Does the spark look the same?
If not replace cap and rotor. If spark at coil is weak replace the coil. You have spark, just not enough of it! Also may have to replace spark plugs drowned with fuel. All of this is based on info. given by your post. I am assuming you have correct compression propper fuel and clear exhaust path.

Get NEW plugs.Do a compression test on ALL cylinders and if ALL over 110PSI , add a 1/2 teaspoon of oil to each cylinder as you re-check compression-- it should go up a bit with the oil added. IF compression is acceptable , THEN put new plugs into engine and start...........maybe.....sounds like cylinders got washed down with gas and starting fluid. And your fighting a losing battle trying to start an already flooded engine with fouled plugs(clean or not). Good luck ........please reply if this actually works........won't be the first time...