A few weeks ago my '94 850 with 147K started making terrible noises while running. Then when I tried to turn it off, it kept running! Of course, when I got it to the mechanic, the noises had stopped and it turned off perfectly and started right up again. He couldn't replicate the problem but since my teenage daughter normally drives the car, I wanted it fixed. So he replaced the ignition switch. It worked fine for a few more weeks, and then 2 weeks ago, the noise started again, and I couldn't turn it off (the engine kept running). Eventually, all the lights came on on the dashboard and I could then shut it off (this took perhaps a minute or two). When I tried to restart it, it was dead. Had it towed back to the mechanic who put in a new starter. All was fine for a week, then the noise started again (this happens when the car has been running for about a half hour)and I couldn't shut it down again. Once again, back to the mechanic (of course the noise stopped during the drive over there - it stopped when I went over a speed bump). He says the starter has burned out! One of his other mechanics did hear the noise I was trying to describe - he thought it sounded like a belt screeching. My husband thinks the noise is the starter coming on while the car is running - the mechanic didn't think it sounded like a starter. Who knows? Anyway, the shop is baffled and I am at my wits end! Any suggestions? Thanks for your help.