Need some help
 

Need some help here

First off, I own a 1999 328i. 197k miles. Love the car

Here's the problem. When I started it a few days ago, it idled rough for about a half minute and the check engine light came on. After the 30 seconds it settled down and ran smooth again, and didn't become rough. The check engine light stayed on, however, and is still on. I stopped after about 10min of driving to pop the hood and check for any visual problems and just do a quick inspection. Nothing. The EML light flashed on during ignition when i turned it back on, which i think is normal, but aside from that and the check engine light I've had no other warning lights since.

Does this pose a significant problem or just is it just a product of the car being 17 years old, and if it is a problem, does anyone know what the cause is? If I need to take it in I'd like to be armed with some information.

Thanks