Rep Power: 0

I have a 2001 Civic LX and I have been having problems with the immobilizer system. For a week or two, my stereo would skip when going over bumps like a CD changer back in the day (it's not a CD changer). Then the car stalled while I was in first gear (at least I thought it stalled) and I tried to restart it realizing that the car was already on because the ignition switch made a loud grinding noise. The green key light began blinking randomly while driving, although the car would always start. I switched the key to a newer key the problem went away, so I thought the problem was the old key. The car drove fine until today when I was driving (with the new key) and the car's electrical shut down while driving. The engine remained running but the dash lights, stereo, etc. shut off. I shut the car down, it started back up fine and I drove it the block or so back to my house. Thoughts? Bad ignition switch? Bad immobilizer?

 
Rep Power: 242

I would suspect an ignition switch or other issue. If the immobilizer where bad it would immobilize the car (I would think), engine off.

Remove the stereo to see if there are any loose wires or something is rubbing. Is it an aftermarket radio or stock?

 
Rep Power: 517

Recent timing belt service? Recent alternator or belts?

Are the alternator bolts tight?