2001 GMC Yukon Gas line

My truck will start up fine. But will stall out if it sits for about 15 seconds or if I push the gas it will stall automatically. It was fine yesteday. The gas was a little low, so I thought it was that but I put gas in it and it is still doing the same thing. I started it this morning let it warm up 15 minutes it was fine when I first started driving, then it just cut out. Know I can't get it to go any where. Need to know what it may be?

Thank you,
Angie