2004 GMC Envoy Electrical Issues

The gremlins are loose in our 2004 GMC Envoy! We have been experiencing some electrical problems. The check engine lights comes on for several days then goes off, a check indicates a thermostat issue however the engine does not over heat. Sometimes we get in the car and the radio station has changed. My wife was in the car one day and I closed the engine hood and the radio station changed. I was driving thru a parking lot and drove over a speedbump, the interior lights came on and the chime for the ignition started dinging for a second or two then everything went back to normal. Yesterday the check engine light came on. When I tried to set the alarm the doors would lock, but the alarm wouldn't chirp and a low sounding buzz came from the alarm. When I set off the alarm, all I got was a buzzing sound. Today the check engine light is off and the alarm works. Do you think it needs an exorcism?