MIL mystery

Actually I have two mysteries that might be related, but I don’t think they are. Perhaps Car Talkers can clarify. 2009 Hyundai Accent, purchased in October, a shade over 4800 miles.

Mystery #1: In the middle of the night a car horn went off in my parking lot. Naturally I went to check if it was mine. I was thinking there might be something wrong with the alarm system or it was tripped, even though no lights were blinking. I de-armed and re-armed the system twice, once after turning the engine on and letting it run for about 5 seconds. The horn noise continued and the car turned on and ran normally. It eventually stopped, and I don’t think it was my car, but I am not certain.

Mystery #2: About 6 hours after the above incident I went down to leave, turning on my car, and it was a bit shaky at turn over and while it ran. The instrument lights that are supposed to come on when the ignition is turned on all came on. After a few seconds I noticed that the MIL light blinked about three or four times and then went off. I turned the engine off, waited a few seconds, engaged it again and it was fine. No shaking, no MIL. The subsequent starts, and drives, after finishing at my destinations were also normal. No shaking, no MIL.

Here are my queestions: are these two incidents (well, one is a possible incident) related? If it indeed was my horn wouldn’t my battery/charging system light have come on on start up? And what is going on with my MIL? Should I be worried about the emission system or engine?

I guess the real test will be tomorrow morning when I leave for work.

Thanks for any answers you can provide.