The fuel rail on a 2000 Dodge Ram is located on the
top of the engine, towards the
back (rear) of the engine bay. Its exact position will vary slightly depending on the engine (e.g., 3.9L, 5.2L, 5.9L). However, it's always on the intake manifold, near the fuel injectors. You'll see a long, horizontal metal bar with several injectors connected to it.
Because you're working with fuel, be extremely cautious and disconnect the negative battery terminal before attempting any work near the fuel rail. Improper handling can lead to injury or fire. If you are not comfortable locating or working on this part, consult a qualified mechanic.
