[Corey D]

I have an 87 LX with a 93 Gt cluster, the volt gauge moves rapidly up and down while the car is on, anyone know what would make it do that?

 

[need4spd90]

not sure what your case is,but there are wiring differences between the 87-89 and the 90-93 clusters
http://www.stangnet.com/tech/cluster87-93.pdf

 

[Corey D]

not sure what your case is,but there are wiring differences between the 87-89 and the 90-93 clusters
http://www.stangnet.com/tech/cluster87-93.pdf

yeah the engine and everything is also 93 so it has the harness for it