GM Genuine Parts Fuel Injector Rails are designed, engineered, and tested to rigorous standards, and are backed by General Motors.These rails are connected to the injectors that are mounted just above the intake manifold on an engine. This rail feeds the injectors to supply fuel into the combustion chamber to be mixed with air for combustion.These rails are connected to the injectors that are mounted just above the intake manifold on an engine. This rail feeds the injectors to supply fuel into the combustion chamber to be mixed with air for combustionGM Genuine Parts are the true OE parts installed during the production of or validated by General Motors for GM vehicles. Some GM Genuine Parts may have formerly appeared as ACDelco GM Original Equipment (OE).