Speedometer up & down when idling, car cuts off at low idle
My car has an automatic transmission.
I think you mean that the tachometer is going up and down, not the speedometer.
If the tachometer is going up and down and then the engine stalls, it's an indication that the engine has a major vacuum leak or a defective idle air control valve. The vehicle does not have a common problem that causes the stalling so I would recommend having the engine idle issue checked to see if a vacuum line came off the engine, or the intake tube between the throttle body and mass air sensor is broken or came loose.
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