I have a 96 Blazer that gives me trouble starting every once in awhile...Ive changed the cap n rotor,coil pack,fuel filter and have done a tune up on it. Have even shot starting fluid into the carb,NOTHING....she'll crank,just WONT turn over. Then after a few days and sometimes a few hours later BAM,she starts. This prob is really starting to get annoying,any ideas.

 

You don't have a carburetor, it's fuel injected.
Take a fuel pressure gauge and follow through the steps in 96+ Fuel System Diagnosis. Come back to this thread and let us know what the results are.