I have a 91 F350 460ci and its tachometer is reading around 3000rpms and stays there when on and even when I rev up the engine? I am thinking a short or bad ground? No other issues on any other guages and no lights on.

 

My tachometer in my 1992 5.0L F-150 is doing the same. It reads about 3,000rpms whenever the ignition is on whether the engine is running or not. I am mainly concerned that the computer may think the engine is running fast and may be supplying too much fuel for it. Any help or ideas?
Alton

 

The computer doesn't run off the tach...

 

Same thing happening in my '92 F-150 5.0L! Any help would be appreciated!!