The 365-plus-horsepower 6.6-liter LMM Duramax featured direct injection, a Bosch high-pressure common rail system, and a maximum injection pressure of 26,000 psi. While considered an overall reliable engine, the Duramax fuel lines, and the rest of its fuel system, can be problematic. +Read more
This generation of the Duramax is prone to throwing a P0087 code for low fuel rail pressure. Symptoms include reduced performance and higher exhaust gas temperatures. Low fuel rail pressure can be due to many factors, including leaking fuel lines, clogged injectors, or a dirty or clogged LMM fuel filter. Additionally, the fuel system’s Bosch CP3 injector pump can also wear out over time; adding a lift pump can help alleviate the amount of stress put on the pump, prolonging its lifespan.