2003 4.6 just dies while driving
 

Have a 2003 crew cab 4.6L. 153000 miles and plugs changed last yr. Have had a small miss sometimes but goes away but the real issue. Filled gas tank and when starting it just turned, no fire. Actually almost run the battery down. Never happened before. Finally after a period of sitting it finally started. Made it to work. Few hrs later had to go somewhere and it just dies while driving. Absolutely no sign of it going to happen. Same issue as at gas station, just turns. after a period it started ran good. on way home did it again same situation and again after a period it started. All no misfires or sluggish like gas problem. Where can I look for possible issue. Pretty much ruled out alternator, those usually, if diode(s) go bad it doesn't start but that's not thing here. Need guidance, I have done engine repairs in my many many yrs driving just need a quick pinpoint areas. I am an electronics tech with PLC experience so I can troubleshoot very well. Time is not on my side when off from work is the reason for assistance for quick troubleshooting.
Paul