fox body 1989 rpm not working

[Jean-Marie GT]

hi . i have a 89 gt and my tachometer needle go down when i start the car. sometime she start bouncing but she don't react to my idle .
when a stop the car she return to is place .i refresh the weld behind the tachometer and i clean all the contact behing the cluster.

last years the needle was reacting with my idle but sometimes she was bouncing . i started last week for the first time after winter storage and now she dont react.
.can somebody can help me
thx

 

[ras50gt]

Did you solve this issue? My tachometer needle doesn't bounce but it goes the opposite direction when throwing a rev.