is my fuel pump failing?

Why not hook a shop fuel pressure gauge up to the central throttle body and run the hose up so you can tape the gauge to the bottom of the windshield. Then as you drive you can see if the fuel pressure holds up to the specification which as you know is around 60 psi or so for GM's vortec fuel injection. Of course fuel volume per unit time is also critical, but you can start with the pressure measurement.

http://www.jcwhitney.com/autoparts/ItemBrowse/c-10...

http://www.autohausaz.com/html/fuelpumps.html

http://findarticles.com/p/articles/mi_qa3828/is_19...

Carburetor, you say? It would be a low pressure fuel pump, quite possibly engine mounted, and those often squirt gasoline inside or outside the engine when they die. In fuel injected cars I've never had any warning - the pump just suddenly died and stayed dead. But that's academic. Since it does not run when you put starting fluid in the intake you have a problem beyond fuel. You have a spark of some sort, so at this point I think we need to know the make, model, and year. I am suspecting the timing belt or chain may be at fault.

If you have misfires you should have a check engine lite on. If so go get the codes read at auto zone and bring them back here. if no engine lite on you could have a defective throttle position sensor (TPS). The symptoms don't sound like a fuel problem. Get a fuel pressure check and check the fuel pressure regulator if you suspect pump or filter problem. NEVER replace any part till you know the problem.

yes a clogge dfilter will cause this but som will old plugs and leads.If its and after market pump then it prob will be louder than your used to.If its only just gotten louder then it maybe because its tryin to push fuel through a clogged filter.try the filter and see how you go.

yep, a dirty gas filter can do all that stuff, it will get so bad, it wont start at all.