2003 yukon 5.3 ran outa gas put some in now wont start?/??

You have air in the lines. Disconnect the line from the fuel filter for it is the easiet one to do for they snap in and snap out . To snap out a special tool is sold at auto parts stores for under ten bucks. Next turn the key to the on position. Do not start the engine just turn the key to on only for 5 seconds. This will activate the fuel pump. Have something uder the line to catch the fuel squirting out. After you have done this a few times fuel should be about 5 ounces or more in the can that caught what cam out. Reassemble the lines and try to start the engine after turning the key to on about 5 times to prime gas to the engine first

Good chance that the fuse may have blew and needs to be replaced. If the fuse is still good, the bad news is the fuel pump may have burnt it self out and will need to be replaced. The fuel it self is what keeps the fuel pump cooled and keeps it from burning it self up. Good luck and start with the simple and check the fuse. Good luck and keep me posted.