First of all, let me thank GreaseMonkey for the highly educating answers. Here is one more in regard to my civic. I am now keeping a multi-meter in the car at all times... thanks. My car will randomly decide to run very rough. If I keep the A/C on it will not idle. Even with it off, it will run rough and barely idle. However, 75% of the time this never happens. Just wanted to throw that in the mix to see if it provides any clues to the possibilility of the ECM failing. Also, I feel like my mpg is lower than 2 years ago.

thanks,

-william

The symptoms you describe could easily be related to a failing ECM. Actually, I recommend replacing ECMs on Hondas every 120,000 miles or 10 years, whichever comes first. They are not bullet-proof, as many people think. I've seen many, many ECMs go bad on Hondas.