Relativly new to this forum but you guys have helped me in the past. I have a 2003 F150 with 4.6L vin W, it had been running good until the other day after i had ran it i shut it down and upon start up it immediately died. After several attempts of starting with no throttle applied i started it with throttle applied. At this point i could hear a loud rattling noise from passenger side valve cover. Sounds like a cam follower or valve lash adjuster. Truck had thrown an egr code with CEL a few days before but light went out. I forget the code number but had something to do with EGR sensor circuit A low. I ignored this as the truck did not change in performance in any way and the CEL went out on its own. I cleaned the IAC today and now the truck dies upon start up w/o applied throttle only when warm. cold engine starts great. I am confused as to what this could be please help

 

Read the codes and post the numbers, please. Pull the valve covers and take a look at things.