Note: The fuel injector sleeve is a crucial component of installing a Dodge 5.9L injector for model years 2003 - 2007 and should ALWAYS be replaced. Leakage between a used fuel injector sleeve and a newly installed injector will cause operational complaints including hard, hot starting and hard to find rough idle complaints. Contaminates that collect in the fuel injector sleeve can dislodge and damage newly installed injectors. Replacing the fuel injector sleeve whenever an injector is installed minimizes these potential problems. The fuel injector sleeve also includes an edge filter as the last line of defense to protect the injector from contamination. Over time, the edge filter deteriorates and allows larger particles to pass into the injector.