I have a 96 blazer it will turn over and fire up but dies out shortly after. If i feather the throttle it stays running but if i let off it fluctuates for a few minutes then dies. I have changed cap rotor plugs wires installed a new air filter housing and map sensor i have also cleaned the maf sensor and throttle body out any help would be great! Also i have checked fuel pressure which is right around 55 60 psi