So today I was driving down the freeway in my 2003 Monte Carlo SS with a Turbonetics kit. Anyway, I was going about 70 mph when my car did somewhat of a jump and I think it turned off and back on. I say this because all of my needles dropped on the dash then all my gauges came on. Any idea what this could be? I'm guessing a bad ground somewhere?

 

Bad ground is possible. Bad grounds cause all kinds of weird electrical anomalies.

Another thought - a faulty ignition switch / circuit. I have an old car that did what you described quite a few times. Turns out one wire on my ignition switch was damaged sometime in the past and was partially broken. If it moved a certain way, the car would just shut down as if I turned it off. Then it would come back to life, sometimes a fraction of a second later, sometimes a couple minutes later. Wiggling the wires coming off the ignition switch and reproducing the problem while sitting in the driveway finally clued me in to the problem source.