Does it twitch? Is it in synch with the other gauge that'* giving problems? The gauge itself is electrical. Check the connectors on the back of the instrument panel. Short of that, look for a vacuum leak.
They both twitch like all get out. The boost gauge is just all over the place....and I know the boost gauge isn't right when it say'* I'm running 10 psi at idle. And I don't think my OP gauge should twitch either. Hence why I thought it was a sensor. How many vaccum lines are on these cars?
My 95 is doing the same thing. When you are on the gas (cruise control set) it stays at 10 psi. The OP is ok on mine but the temp gauge spins in circles most of the time, one minute at 0 then 190 then 260, then the process begins again. If you find out anything else post it for me too.