Tach is stuck

[MR.Anger]

So when I start my 92 Ranger 4.0..the tach spins around like a horror movie clock and when it starts and runs.....the tach is stuck and 4K rpms...but when I take it past 4K rpms it works....then when I drop below 4K rpms it goes back to stuck...and when I shut the truck off it bounces around then falls back down to 0 rpms.....what the hell is wrong with it? lol

 

[BRUTUS_T_HOG]

ignition module could be going bad. any running problem? you usually get codes for the IDM circuit or SPOUT circuit when this happens

 

[feellnfroggy]

Get yourself a 30 dollar small tach from auto store and install it, If it works your factory tach is bad. If not then address the other issues mentioned above and you still have a really cool tach.

 

[LearjetMinako]

Sounds like the cluster tach is going out. My temp gauge flinches as the engine warms up. But if I can get the engine fully warmed, its works normally.