[wolfox]

That fuel pressure reading is a bit on the low side. With key in the run/on position but not starting the engine, it should read in the neighborhood of 60-62 PSI for a CPI Blazer Vortec. FIrst thing I would check though would be if the battery is completely charged. A low battery from multiple start attempts can cause weak fuel pressure readings. Make sure too that you are getting a spark from the coil. So, slow-charge that battery overnight at 2 amps and try to get it to fire over, or use a booster battery and cables, check for spark, and see if that helps. If fuel pressure it still too low and you have a spark, I would pull the upper intake to inspect for the regulator, injector, or fuel line leaking before you go and pick up a fuel pump. If it's leaking/spraying gas when you do a key on, no engine start, you found the problem. If it's not leaking, then I would suspect a fuel pump.