i was going down the highway and it just shutoff. I tried to start it again after and nothing would come on except the radio. It did this yesterday morning but the key wouldnt turn all the way and it wouldnt go back to the lock posistion to take the key out.I eventually got the key to turn but it wouldnt turn on anything but the radio at first but eventually started working fine. Also the speedometer has been bouncing around all the time now, dont think its related but i put it out there anyway.any ideas?

its a 95z28 with an lt1 and exhaust from a 96-97