This seems more like a connector or pre cluster issue. If the speedo and other stuff also went wonky..then I'd think cluster.

What types of behavior..low readings..bouncing back and forth?

I had that same issue with a '93 SSE. Tach and speedo always worked. The rest, whenever they felt like it. No rhyme or reason as to when. I had the dash apart 3 times to clean the connections. That didn't help. Finally, touching up connections on the circuit board with a soldering iron took care of the problem. Work on the larger connections where the boards connect together, and any place where flexing caused by heavier components can occur.