1998 GMC Suburban 98 Suburban cranks but won't start - Bad

Hi, I have a '98 Suburban which cranks/turns over and nearly starts (and in fact sounds like it has started, briefly) and then "stalls". The tank had 1/4 fuel at the time so I added 5 gallons of clean 93 octane gas and some STP thinking I might have water in the existing fuel. No luck, same problem. Also, a day or two prior to this happening, the vehicle stalled as I was backing out of a parking spot, but it did immediately restart and ran fine for another day, until the above happened.

I tried switching the AC relay switch with the Fuel Pump relay. No luck, same trouble. Does this sound like a bad fuel pump? If so, is it something I can replace on my own or am I better off paying to have it done (I have few tools and no place to work on the vehicle).

Also, the vehicle is presently stuck inside a parking garage, so any thoughts on getting it running temporarily so I can get it home or to a garage would be greatly appreciated.

Thanks very much,
JB