Hey guys, I recently put a reman 5.4 in my cousins truck. I'm having a nightmare with it . Lean codes and misfire on 2,3,4. As well as random misfire. New intake, new injectors, new COPS, new plugs, new fuel and air filter, new fuel module, new manifolds, new y pipe and cats..... I'm ready to scream....oh ran new vacuum lines too

 

New parts don't necessarily mean good parts.

 

Turns out that it was a bad cam phaser on bank 1. Warranty by Ford .