Lately my spedo has been jumping around when sitting still, clears up with any increase in rpm. could it be a grounding issue?

 

Yes, it sounds like the cluster ground is flaky. Jim Lane did a writeup about putting LED's in the dash, he also covered repairing the cluster connections.

 

Thanks Dave,
Just a little update on the grounding,

Previously my gauges would occasionally wander up and down the scale and then start reading correctly again and now after I soldered all of the connections on the circuit board



and added the external Ground,



they do NOT move at all except for my Fuel gauge that constantly moves from "1/2 " to "E".

Also with the LED's I can now see all of the gauges easily bathed in Cool Blue light instead of the stock Dim Muddy Green.



I highly recommend this upgrade to all of you.
Thanks.
Jim