i had a difficult time figuring out the lean codes on a mans 97 F250 w/5.4. After checking all the vacuums and everything checked with snap-on scanner,fuel pressure o-k, volume o-k; wound up just pulling the fuel filter, shook it real good and poured thin mud out! It seems it took a while of driving for the sediment to collect around the element and lean it out. I was even told they put a filter on about a year ago. the guy was probably lied to since they are so damn hard to change