Hi y'all new here should of came here forever ago. I've got an s10 blazer that cranks all day but will not start. List of parts that have been replaced: Fuel pump, fuel filter, CPI unit, in/out fuel lines, intake gasket, intake plenum gasket, distributor, timing chain/gasket,ign coil, plugs/wires, tps, egr, iac. Tests and results: Inline spark test weak spark after first crank then no spark all cranks after, fuel pressure test hits 62 psi at koeo then less than 5 seconds drops to 40 psi. It seems the injectors are spraying out my spark and I'm lost trying to find what would cause the fudge in fuel delivery to fuel/air mixture and if I'm anywhere near the right track of narrowing this down? Any and all suggestions are greatly appreciated. Thank you looking forward to some new insight on this challenge had it running great then one day I was driving on the interstate and was doing 65 on a hill and when I kicked it down to overdrive it got to 68 mph and the motor shut off but all my gauges were still reading me fuel lvl, rpm's, oil pressure, battery voltage but the motor would not start back up.

 

Well regulated fuel pressure is not good to start so you have a fuel pressure regulator gone bad or could possibly be the fuel pump itself. You must do a Max Out Put test on the fuel pump. It should be 73 to 108 PSI at the outlet of the fuel filter. Pressure at the Service Port must be atleast 60 PSI and not bleed down to less than 58 PSI after 10 minutes.I see you replaced the pump but if it is not an AC Delco or Delphi unit you could have a problem there and did you use the New MPI fuel injection Spider or the same old stock type spider with poppet valves. The regulators on them have issues too.

 

Just in case you haven't figured it out yet try the ignition control module and or Coil pack