truck is an 04.5 lly with 15k trouble free miles. Started truck and I usually let it run for about a minute before driving. Truck ran for about 15 seconds before dying...just like it ran out of fuel. Guage shows about 1/8 tank and trip comp. shows 71 miles to empty. low fule light is NOT on. truck is sitting on slight grade where the drivers side is slightly lower...but not much!!! It's dark out now and I don't have time or equipment to properly check...if I knew what to look for in the first place. Any suggestions overnight would be greatly appreciated.

Sounds like you are out of fuel. GM has alot of problems with the fuel gauge reading properly. You will have to put some fuel in it and prime it.

Have you changed the fuel filter? It could be clogged. I'd start by changing the filter and bleeding the system AFTER you put more fuel in the tank.

It sounds just like mine did when I got the water in tank and it froze. That is just like the filter is plugged. Mine would start and run for maybe 5 to 10 seconds after I waited a while. I would start with some fuel and then a new filter. And Yes there is a problem with the fuel gauge sending unit. I had to have mine replaced.

Something similar happened to me. I tried to change my fuel filter but could not get it off without a filter wrench. (the one I had would not work) Turns out that I turned it by hand just enough to let some air in. The result was similar to yours it would run for a few seconds then die. I could wait a few more then same thing all over.
I replaced the filter and not a miss since.

Same thing happened to me last year in my '02. I was cruisin' down the GSP at 75mph and she shut off. I popped the hood and found that my GM Goodwench guy didn't tighten the bleeder onto the new fuel filter enough and she got a little air in 'er. Was off and rollin' in no time.

Ed

reprime the filter. if no luck, may have some water in the system. i wouldn't go by the dic reading on miles left until empty as readings are easily scewed. if you have a new fuel filter, check for any seapage near the bottom. if no seapage, then repriming should do it. upon seeing some fuel out the bleeder, tighten it up and pump a couple more times. should fix your issue, hopefully.