| On princilpe I would check all fluids because that might give you some information. Also I would check your spark plugs and check all of the coils. You could also take out and clean your fuel injectors (if the problem was not so bad I would just say put fuel injector cleaner into the gas tank, but I would not want the car running a lot as is) The ding ding ding could have been related to a warning, it is possible that a bulb is out for your warning lights (or disconnected by previous owner). If you can check all of the above and still come up with nothing, I would get the car somewhere that can pull the engine codes for you. If possible not the dealer because they will charge you a lot for anything that they do, so try to find a reputable mechanic who is trained for BMWs perferably factory trained. Good luck with it, if you find anything wrong while checking let us know, we might be able to narrow the problem down with more info. | 
