'99 diesel with intermittent engine light and rpm gauge goes to zero even though the engine is still running fine. I have 120k and figure that I just have another sensor going bad. Isn't this problem the crankshaft speed sensor that is creating this problem? If I am correct, where is this located?

 

sounds like it may be a crank sensor issue. . .I hope I'm not lieing to you but it should be at the front of the engine below the harmonic ballancer.

best thing to do is hit up autozone and have them pull any codes then get back with us on it.