Help! '99 Yukon Turns Over-won't Start

IT WAS RUNNING PERFECTLY, SUDDENLY WOULDN'T START. LATER, IT BARELY STARTED. THEN COUGHED AND SPUTTERED, ...SEEMED TO RECOVER AND EVENTUALLY DIED. TURNS OVER BUT NEVER CATCHES.
I DO NOT HEAR THE FUEL PUMP. I NEVER NOTICED A SOUND WHEN IT RAN. THERE IS A CLICK IN THE FUSE BOX UNDER THE HOOD IN THE RELAY. IF PROPER FUEL PRESSURE (60-65PSI) AT IDLE WHAT IS PROPER THE PRESSURE WHEN IT IS NOT RUNNING? I GOT A VARIABLE
READ OF MAYBE 10-20PSI. MAYBE AND IT WASNT CONSTANT. IF IT IS THE FUEL PUMP, HOW BAD IS THAT TO DO AT HOME? CAN I SAVE MONEY BY DOING IT MYSELF?
HOW CAN I BE SURE IT IS ONLY THE FUEL PUMP? IS THERE ANOTHER FUEL FILTER BESIDES THE ONE I CHANGED UNDER THE DRIVER'S DOOR?
IS IT POSSIBLE THE TIMING CHAIN IS BAD?
IT WAS SUGGESTED THAT THE CAT CONVERTER COULD BE CLOGGED. I DROPPED THE EXHAUST PIPES TO SEE AND IT WAS NO HELP.
ANY HELP WOULD BE APPRECIATED.:banghead:

Welcome to AF, the press., key on, when first attempt is made is 60-65.

I've got the same problem with a 2002 Yukon XL. Car starts fine, but every week or so it won't start. Turns over fine, but won't fire up?

Additionally, once a week or so, it will just cut off while driving down the street. Battery light comes on and car goes dead - doesn't idle down, just cuts off....and I have to wait approx. 2 - 3 minutes to start again....

Any ideas...it's not the fuel pump.