I had the same thing happen to my 94 a couple years ago. i was driving when my 3 gauges on the right went haywire. I pulled over and shut off the car. It gave a quick glance through the moon roof and didn't see any alien ships so i assumed "The man" with his "satellite microwave thingy-bobbers" was messing with me. I cursed myself for leaving my tin foil hat at home. Anyway i put the key to the "on" position and watched to see my gauges do the "flip test"(lotsa quotes eh?). The speed and tach flipped normally but the temp, boost, and oil pressure started, stopped, continued and started flipping out again and went to random positions and stayed there. As i drove they moved or looked like they lost power for a split second and did the test flip. I took the assembly out of the car and brought it down to the dealership. I told them what the problem was and the guy said it needed to be rebuilt. He said it would take about a week because they needed to ship it out to do it. I can't remember how much it cost. but i want to say it was about 180$. I got it back and installed it myself. Everything was fine for a few days when it went berserk again. I brought it back and they said they would have it fixed again for free. And this time i had them do the install(which was free too). since then i have just recently had the temp gauge start displaying whatever temp it decided to show. Nothing worth fixing in my opinion. Maybe when it start flipping out i'll have it fixed again. But i don't trust the dealership that i have to go to now because the one i liked closed down
Sorry about the length of the story!
I just can't seem to figure out why i have carpal tunnel....