More engine noises in the 330..
 

Tonight driving home from Portsmouth the engine was making strange noises again. It was running kind of rough on the highway. At the stop at the end of my exit, the RPMs kept dipping below the idle marker, then going up, then dipping again. I'm worried that the engine coils are going to go. The engine feels the same as it did when that happened to me earlier. It seems BMW engine coils only last about 50,000 miles... they failed on my X5 at about 52,500 miles and they failed in the 330xi at 52,000 miles. I hit 104,000 miles as I pulled into my driveway tonight and it seems that they're due to fail. Any other ideas on what it might be, though?

document the weird noises and bring it to the dealer... Have them look at it.

he's outta warranty so that might be a costly trip.