sdrr

I have a 96 f150 4.9. After driving it will not start after setting for 3 or 4 hours.It will start when hot. when I do get it started when cold, it will start every time for days. Until it gets hot again. The fuel pump comes on when key is turned but no start.I have found If I leave the key in the run position, often, after 15 sec to 3 min the fuel pump will buz and the truck will start. truck runs great once started. check eng light does not come on while runing. I have changed the fuel pump (return gas was going to wrong tank),fuel regulator,power module,coil,cap, temp sensor, and the emc (computer). Seems like something is telling the ecm to shut down.
HELP

shoudust

Clean your grounds all of them, start at the battery and follow to the frame,to the block and anywhere else it goes, pull it off the frame and sand to bare (shiny) steel and the same on the block. My 91 bronco had the same problem and I thought it was the starter but ended up being the grounds!