M3 1998 sedan with 67K miles
runs great, but it starts hard.
Upon starting, there is a loud squeak that clearly is coming from under the hood. When I first put the car in gear, the squeak continues for 10-20 seconds and the car runs rough. Then as I start to accelerate, it goes away and does not return, even at stop lights, etc. If I turn it off and restart within a relatively short time, even a couple of hours, no squeak. But, without fail, if it sits for long periods of time (overnight or in the work parking lot all day) - same problem. Had belts checked by bmw dealer - he says they looks fine. He can't seem to find the problem.