Fuel pump problem?
 

So I have a '97 Chevy Blazer 4.3L and it decided to stop starting on me yesterday. It cranked but wouldn't start. Ever since I've had it it has always started hard...I would usually have to turn the key twice to make it start while leaving it in the on position for a few seconds in between the two tries. It also has a hesitation problem when I drove it. It would buck and surge and not want to go faster...like it wasn't getting enough fuel. When it wouldn't start I shot some starting fluid into the carborator and tried to start it and the engine turned on for a second and then shut off. So is this definitely a problem with the fuel pump?

Oh and I already had the fuel filter changed prior to it not starting as well

I'd almost bet it is the fuel pump, but just to be sure, I would check the fuel pressure.

replacing mine - was only getting 60 psi max with the gauge hooked directly to the line from the pump - should be 70 - 108ish

other thing it could be is the pressure regulator not holding enough pressure to make the injectors work

Definitely do a fuel pressure leak down test. Fuel pressure at the test port should between 60-66 PSI with the key on, engine off. It should then hold pressure above 55 PSI for at least 10 minutes after you turn off the key. Anything less than that you have a fuel delivery problem. Like Roypai said, the next step would be to test the pressure directly from the fuel pump (easiest to modify your tester to connect to the line where it connects to the fuel filter) and you should get between 70-108 PSI with the key on. Less than that and you have a pump problem.

Do those tests and post up your results here so we can help you further.