when i start my car it starts missing or shaking if i sit in park, and if i take off it will loose power and miss fire. but if i cut it off and on a few times it will stop.
My car has an automatic transmission.
From the symptoms described, it does seem that your BMW is unfortunately experiencing engine misfires. However the source of these misfires can really be caused by multiple sources, from worn out spark plugs, to even a failing mass air flow sensor. Since you are able to, in a sense, trick the car into operating correctly, from my experience I would say that the problem is electrical. It is very possible that one or more of the ignition coils have gone bad or that there could be a failing camshaft or crankshaft position sensor.
Coils, plugs, vacuum leaks and many other culprits can be behind the cause of your BMW's misfires. Since this is a situation involving a long list of possibilities, I would highly recommend getting in touch with a certified technician, such as one from YourMechanic, who can stop by and go over your BMW with you from bumper to bumper and diagnose your running problem. Some handy information you can have ready for your mechanic include the mileage of your vehicle, information on any previous work performed recently and if the check engine light is on and whether it blinks while these symptoms are occurring.
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