About a year ago my 2001 F-150 5.4 liter truck suddenly would not start, there were no warning signs, it was running fine when I stopped at Walmart on the way home from work and it never started again. After towing it home I diagnosed that it was a fuel issue and ended up replacing the fuel pump. I replaced the fuel pump and it ran great for about 6 months.
6 months after replacing the fuel pump it would randomly have trouble starting on hot days, if I kept trying it would eventually start (for some reason removing the gas cap seemed to help). Someone told me this could be an issue with the battery so I replaced that, but the difficulty starting continued and then started happening in all temperatures. About that same time it started to run rough, like it was chugging and starving for fuel until it eventually it just did not start any more.
I suspected a fuel problem again so I checked if it would start up with starting fluid and it did (for a few seconds then would die). I assumed either the new fuel pump had again gone bad, or that the tank was not clean and debris were clogging the pump (I did not clean the tank with the previous replacement). Today I changed the fuel pump and cleaned the tank thoroughly, but when I got everything back together it still will not start.
It still starts and dies with starting fluid, but will not take hold of the gas. I also verified that the pump is in fact pumping by draining the fuel at the fuel filter till there was none in the line, reconnect and attempt to start, then check for fuel in the line and there was plenty... Not sure what my next step might be. Any help would be greatly appreciated.