I've tried searching the forum but I can't find anything specific to all of my issues. And I can't tell if its all related for sure or not.
here's my problem:
i have a 95 s10 blazer v.6 vortec
it has a rough idle almost like its trying to find an idle, rpms jump slightly on and off, there is a rich fuel smell from the exhaust, hard starting I have to give it gas to get it to turn over, but not everytime I start my truck. And my fuel mileage is pretty terrible about 9 mpg (i'm running 31'' tires but still shouldn't be quite that bad I don't think) also it isn't throwing any codes. I took it to the shop my step dad works at and we were trying to figure it, we couldn't check the fuel pressure because there gauge was broken. So we are thinking its possibly the fuel injectors ( I hope not cause spider injectors are EXPENSIVE) or the fuel pressure regulator. Also plan on doing a full tune up just in case (spark plugs, wires, distributor cap and rotor). Any idea what it is? Any help would be appreciated. Thank you

 

1995 could have a couple of different systems. Each one uses different diagnostics. Which system do you have?

This is a CMFI system:





This is a CSFI system:

 

I've got the CMFI

 

Classic symptoms of a fuel delivery issue. CMFI uses one fuel injector and it's "batch fired" meaning it squirts fuel to all cylinders each time any cylinder calls for fuel. The system uses two plastic fuel lines in the plenum that like to sprout leaks along with the fuel pressure regulator. First step is get that fuel pressure tester fixed, buy, or rent one! Key ON, engine OFF, fuel pump running, pressure must be 55psi to 61psi and must remain above 50psi for 10 minutes after the pump shuts off.

 

alright I'll give that a shot it will probably be a day or two but I'll let you know once i test the fuel pressure. Thank you!

 

Okay went and rented a fuel pressure gauge from autozone this morning and just checked the fuel pressure. when I turn the key it gets to alittle over 50 psi then just drops. I also started the engine and it gets to 50psi. I'm thinking fuel pressure regulator maybe? my question is that what it is and do I have to buy a whole new spider assembly or can I just change the regulator? Or is it something else.
Thanks for your time.

 

It's up to you but I would replace both the Regulator and the nut kit. Like Cap'n Hook said, it's almost certainly one or the other, based on what you describe.
{the running pressure and static pressure being near the same, which it shouldnt}
Chevy Astro CPI Fuel Injector Install part 2 - YouTube
Nut Kit called 'fuel lines' on that video

Of course that guy replaced everything probably a good idea.
check rockauto com

 

50psi is far too low, along with the pressure drop to zero, that's the problem. The regulator should regulate ~62psi, but with a 50psi reading, the regulator isn't receiving enough pressure to regulate, or its stuck open, (causing the drop). The next step in determining the problem is check fuel pump maximum output pressure. This is done at the fuel line that connects to the fuel filter. Disconnect the line from the pump at filter and connect the pressure tester to the line. There is a special tool designed specifically for this however, with a little creative plumbing work, you can make one for around $40. Parts are available at an auto parts store and a good hardware store. The finished product looks like this:



Or, you can modify your current tester to connect directly to the line. Close the valve, energize the pump and check pressure. Should be 78psi to 108psi and must hold pressure above 50psi for 10 minutes after the pump shuts off. If those tests are ok, the problem is in the plenum and will require removal to diagnose. Basically, at this point you know you have a leak, this test will determine if the leak is in the tank or in the plenum.

 

sounds like fun...alright I let you know how it goes.
Thank you guys for all the help

 

If money is not a concern, you can take one end apart and start replacing parts. If it is, complete the diagnosis and know for sure what the problem is. You're on the right track now and we'll help you through it.