We had this happen a couple of times.

Power seems to shut off then quickly comes back on.

Easy to notice on the radio where a song might seem to skip as the electric goes on and off.

Not just the radio, but easily noticed there.

Battery cables seem tight, grounds seem ok.

Thanks for any ideas.

 

Does it happen like over a bump? Or just randomly for no reason? If you have checked all your grounds Id take a Multimeter to your batter to make sure its producing enough volts while the car is off and while the car is running to see if the alternator is properly charging the battery.

My money is on a loose ground though..

 

anything to do with the main fuse?

Never had an issue with it, but this seems as if it would act this way if there was a loose
connection?

 

the 120main is connected to 2 bolts of im not mistaken, the ones you have to remove to pull it out. Also check your fuses to make sure none of them are corroded, that might be making it a issue.