tachometer sticks at 1200 sometimes

[bigcrunch]

In a 97 U55 when I start it tachometer goes to 1200 rpm I know it is hair above 900, tach then drops sometimes. When I drive it 2000 ish rpm at the same speed my U35 is at 2600, same gearing.

tach it self commonly?

 

[rasouth]

The tach on my '96 either works or doesn't work, most of the time it doesn't. I believe there is a circuit board behind tach and the soldier points may have become loose.

 

[crunchie_frog]

I have had more than one Ford tach from this era have similar failures. I never had any luck finding bad solder joints, just replaced the entire instrument bezel with one with similar miles.