Does not want to stay running

One of my friends asked me to help him with his truck and I know very little about fords but the truck will turn over and sometimes it will start for a few seconds and then die but you can feather the gas pedal and keep it sputtering but it still dies he has changed the fuel pump fuel regulator fuel filter mass airflow sensor tps sensor icm and both coil pacs it sounds to me like a fuel problem but with so many sensors it's hard to tell and none of the parts stores have a computer that is compatable unless you buy one any help would be greatly appreciated