I have a 99 5.4 that has been missing sometimes. Feels like it's running on 7 cylinders. It only does it when the fuel level is below half, and I can almost count on it doing it when it drops to 1/4 to 1/8. It's usually only when first starting the truck and clears up after the first 10 - 20 minutes of driving. It also is alot worse when the temps drop to below freezing. Any ideas?

 

probably time to start looking at doing a fuel pump.

how long has the fuel filter been on there? maybe try that first since its a quick fix