Tach flickers and flashes and shows various readings alot. Mostly ok at idle, worse as I increase the rpms. Occasionally the entire cluster flickers also. Have sent the cluster in twice to be refurbished and still does it. Was told to change the tach filter, but that didn't fix it. Supposed to send the cluster in again. Is there anything other than the cluster that it could be? Also, a new computer has beeb installed. Any suggestions of what to looks for?

bad ground

What is a good way to ground it? Have checked the grounds and have found nothing. Open to anyway to ground it differently. Any ideas will be welcome and tried.

You have ground is the flicker. Now you need to pull out, hand it to the parts counter is have them ship it for inspection/rebuild. Your dash lights on? Then I would assume your ground is completing a circuit and now pull the pod and ship it.