'99 Suburban - won't start - cranks but won't fire

Hello.
Not sure if this is a catalytic converter problem -- our serivce engine light came on at one time, dealership said it was the converter -- husband said its not necessary to change it. So we didn't. Now, 4 months later -- it won't start - it will crank and crank but won't fire. After a while, husband pumped the accelerator and finally it did fire -- fuel must not be getting there? Once it was started, when you press on the accelerator, you can hear it bog down then rev up.? Not sure if it's a fuel filter, or maybe injector problem -- or if we really do need to the the converter fixed.? Any ideas?