1991 s10 blazer 2wd 4.3 has fire and fuel, new timing chain, plugs, & iac. itll crank but dies a few seconds afterwards as if its not getting gas but the psi is right for it and all the injectors are good, so what all could make it do this?

 

Im going to suggest a bad a fuel pump/poissible clogged fuel filter.Replace the filter first and see what happens.