What year is your car? Thinking the gauge probably has a power and ground connection as well, so I would guess that one might be flakey, but hard to say without knowing what vintage it is. The gen 3+ stuff has all those gauges in a single assembly, so I would expect them all to be doing funny stuff if it was a power or ground issue. I think the gauges were all separate on the gen 1/2, so I could see that one having an issue with just one gauge at a time.