I'm not trying to hijack a thread,& I will try to keep it short.now I'm just going to suggest the solution that fixed our 1995 blazer lx 4.3 vortec.
after many problems with everything spider,FPR,Fuel pump & filter we finally figured out there is a hole on the FPR with a small screw inside. so our truck was in the driveway new fuel pump filter and pressure regulator & spider nut kit etc. & still would not run!! so we hooked up our pressure gauge took off the plenum and started screwing in the screw and watching the gauge. it went from dropping pressure from 60 to 35-40 instantly and after adjusting it would pressurize to about 67 and hold at 59 so we reassembled turned the key and she fired right up and purrs like a kitten. I hope this might help someone out. I'm surprised me and my father still have hair left. haha.

 

Your 1995 has CMFI, (Central Multiport Fuel Injection). 1996, like the OP's, and newer, have CSFI, (Central Sequential Fuel Injection). There are substantial differences between the injection and computer control systems. Although some fuel pressure regulators are adjustable, (not all are) it is not recommended to adjust them. If the regulator does not regulate at the proper pressure, replace it. Fuel pressure spec for your 1995 is 55psi to 61psi, (key on, engine off, fuel pump running). Leakdown must remain above 50psi after 10 minutes. Spec for 1996 and newer is 60psi to 66psi with a leakdown spec of not lower than 55psi. Regulated pressure of 67psi on either system will cause a rich fuel mixture and the driveability issues associated with it, poor fuel mileage etc.

 

as I stated I was just telling what I did to fix the problem I was having.which sounded about the same as what's happening here.
I didn't go deep into detail & say that I purchased 4 different fpr's and replaced the entire fuel sending unit. Until after some adjustment to the fpr my truck would not run. having tore the truck apart so many times I truly didn't feel like doing it again. besides it's running so I'm gonna leave well enough alone. take my advice or don't as I said that's your choice. but it fixed mine.

 

Shane, don't put gas in the throttle and don't let the engine start to do the fuel test. If you have to, unplug the coil. Anyway I see the Captain has already moved on to the next step. He will go through the series of tests like a surgeon. If you follow his instructions exactly, you will avoid replacing every other part except the one that might be your problem.

 

Ok i wont i wanted to do the test but got a foot of snow lol i dont have a garage so gonna do it tonight or tomorrow but yes i will listen to the captain he seems very wise with this stuff thanks

 

Sorry it took so long was quite difficult to get the guage connected but results are this, 1st turn of key on was 15lbs 2nd try was 45lbs and 3rd was 55lbs tried several times after that and pump kicked on every time and could not reach any more than the 55lbs let set for 15 minutes and tried one final time which the pressure had dropped to 50lbs after 15 min and last time it went back to 55 again but one thing I noticed today i tried starting it and it only took about 5 tries to start it versus the normal 50 to 75 tries but weather has been cold but today was a freak day here in the northeast and was 65 out so im not sure if that plays any part in all this.

 

If those readings are at the fuel filter, max pressure needs be 73psi to 108psi. It should reach that pressure on the first activation of the pump. Your fuel pump is not supplying the injectors with nearly enough pressure, and it needs to be replaced. Use AC Delco or Delphi pump only.

 

those readings were at the fuel filter front side and have only gotten 55 lbs max all day trying it so my next step will be replace the fuel pump with an ac delco or delphi

 

Don't forget Amazon & Ebay, they can be your friend. Just make sure you're getting a genuine AC Delco or Delphi pump, they can be very deceiving in their description of the part.

 

ok will do