What does it mean when...
 

I drive under this same set of power lines in my neighborhood and the CHECK ENGINE light illuminates for about 3 seconds and then goes out. It never occurs in any other instance.

Now that's definately a new one!

Do you have any mods done to your car?

Please excuse the laughing sound you're undoubtably hearing from the direction of Michigan. I'm not laughing at you, just your symptom. That's positively bizarre.

I assume you drive under these wires in the morning and then at night. Does it happen at both times? What if you repeatedly drive under the wires, will the light turn on and off every time you pass the wires?

Can you drive the other direction down the road in the morning? Maybe the light will come on in the same amount of time.

I suspect that the CE light happens to come on when you pass the wires, but that's just a coincidence because the same situation is being repeated consistently every day.

If that's not the case, and these wires really are causing the CE light to come on, then I don't know what to tell you.

What if you stop under the wires? Will the light stay on?

My engine temp sensor gave me problems a while ago with similar symptoms.

It seems to occur when only when passing in one direction and I would say that it occurs roughly 30%-50% of the time. The power lines are roughly 50' in the air. That's a good idea to next time stop the car directly underneath them. The first time it occurred I thought "oh great, what now." It was the 2nd or 3rd occurrance when I figured it has to do with some interference with the power lines and possibly the ignition system.

I have heard a similar story before; I think it was actually on CarTalk... seems to me the person was driving by a military installation (or maybe it was a school...)

Time to do some research...

Are you in the area of American Electric Power (AEP) or maybe the name has been changed?