2004 Ford Focus Dashboard acts like a pinball machine
I drove about 45 miles today with a number of stops for errands, close to an hour and 15 minutes driving time. During all but about 2 minutes of that, my dashboard looked like a Pinball machine. The needles on all the gauges (gas, speed, temp, tach) swung wildly from 0-the top, all the lights flashed on and off randomly.
There seemed to be some correlation between a change in the light and needle show and minor "bumps" in the road, e.g. the speedometer would go from being pegged at max to 0 and bounce once or twice.
The last two times I started the car up it was normal for about 5 seconds.
This has happened twice in the past year, but for no longer than a minute each time. Today, there was no longer than a minute of normal function.
My first guess, because it's intermittent and seems to relate to changes in the road surface, is that it's a loose ground wire somewhere, but I'm old (from before the days of onboard computers) and not a mechanic.
Any ideas kids? It's a mystery and I would love some help solving it.