I recently bought a 2000 328Ci that has some strange things going on. The car has about 100k miles on it.

The right signal flashes at about double speed most of the time. It used to slow back to normal, but lately it pretty much stays fast. The left always flashes normal speed. This problem has been getting worse.

The dash indicator shows that the right rear bulb is out, but the bulbs are OK. The indicator goes off when I turn the headlights on. Lately, however, with headlights on, the indicator comes on when I step on the brakes.

Third thing is the idle. Its starts and idles fine, but after a few blocks when it is just starting to warm up, the idle sometimes quickly drops off. Usually it recovers, but sometimes it stalls. Once the engine is warm, the idle is fine. It seams like it is loosing ignition briefly and then recovering.

I have had it checked out at the corner BMW service place and they don't know the cause of any of these things. None of the three have any real effect on the car, but they are anoying.

Any suggestions?

Check the contacts on all the brake light and indicator bulb bases for corrosion. The check light circuit is very sensitive to increased resistance, so as a poor or corroded contact will show up as high resistance, and it will throw a check light warning. The double speed flasher indicates that one of your flasher bulbs on the RHS is out or has high resistance.
It's probably time to change your pre-cat O2 sensors - they are only good for about 100K. It sounds like everything is OK in closed loop (default settings) but as soon as the O2 sensor comes in, things go a bit pear shaped. I'm surprised the BMW service place didn't get an O2 code - or didn't they do a fault code check?

I was wondering about a possible O2 sensor. I haven't palyed much with post caberator age cars, but it seams pretty obvious that the thing is confused when the engine is warming up.