I've got an '03 C230k ss, not quite 52K on the clock. I'm on the first leg of a trip, about 3 hours away from town. Car was running perfectly when I left town. I pulled in front of a friends house after 3 hours of driving and the idle is really erratic (up/down/up/down real quickly). There were no malfuntions indicated, and no lights on the dash. The dudes wanted to 'take the Mercedes' to dinner, so we did, about 15 minutes each way. Same idle problem on the way there. after dinner, I started the car up and now the 'check engine' light is on, but still no malfunctions indicated.

Is it even safe to drive? I'm supposed to be taking the car up to ~10K feet elevation tomorrow (thinking not now ...). Any ideas on what this could be? I had the A/C on the whole time, and was going at a good clip (probably averaged ~80mph). I don't think that would have anything to do with this, but thought I'd mention it.

Thanks in advance!!!!!