1997 Chevy Silverado 1500 4x4 will not start. Getting spark checked all fuses, changed rotar - spark plug wires,

Have you checked the fuel pressure? Fuel pumps are a common failure item on those trucks. Pick up a cheap fuel pressure gauge and hook it up to the shrader valve on the fuel rail. With the ignition on and you should have 55-65psi. Even if it's a few psi below spec it could stop the engine from firing.Once you determine the fuel pressure isn't adequate make sure you have a good power and ground at the fuel pump. If that checks out, time for a new fuel pump module. I recommend only replacing it with an AC delco unit, I've heard bad stories about aftermarket replacements.
You could also spray some carb cleaner or starting fluid in the throttle body and crank the engine over. If it runs for a few seconds after spraying starting fluid in you know you have a fuel delivery problem.

If the engine is turning over properly and you know for certain your getting spark on all cylinders check fuel pressure and injector pulse. If fuel pressure is good then check to see if fuel injectors are firing. If you have spark and the fuel system is functioning properly do a compression check on all cylinders. You have to find out whats missing, fuel? air? fire? compression? one of them is missing if it won't start. Gl