Gauges Run Amuck

I recently replaced the motor in my '97 Grand Am for use as a daily driver (29 mpg). Everything was going fine for a month, then yesterday on my way to work, the gauges started bouncing all over the place. They would max out then shut off, go back to normal, so on and so forth. I was wondering what might be the root cause of this. I have read a few posts pertaining to gauges in the GA's and saw that fuses are sometimes succeptible to moisture and may need cleaning. I would figure that they were not completely blown because every now and again, they come back on. Also saw that the ignition switch may itself be corroded, but I would not have even considered this a solution due to not having any ignition trouble when starting the car. Anybody have any suggestions?

Is anything else going out with the gauges? The solution on my '99 was cleaning the corrosion inside the ignition switch. Because different contacts send signals to different components, I had no trouble starting the car or keeping it running, but I would randomly lose all of my accessories and gauges while driving. Could also be a bad body control module, bad instrument cluster, bad ground, etc. It took me a lot of troubleshooting and guesswork before I figured out what was going on with mine.

The corrosion is the problem that I have been hearing a lot about so I am going to start with that. Thanks for the help and information. I'm gonna try that and will keep ya'll updated on the progress.