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Q: Car runs with the mass airflow sensor unplugged. If you plug it in it will die if the car is running.

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If you unplug the mass air flow sensor the car will start. If you try to plug it in while it's running the car will die.

My car has 90000 miles.
My car has an automatic transmission.

This is a sure sign of a shorted mass airflow sensor. The reason it starts with it off is the computer sees no mass air signal and replaces it with an internal memory fake signal to use. This will let it start and will run well enough to get to a service repair place. Leave it disconnected for too long without getting it fixed can start to foul spark plugs and will have other different driving issues. If you need some assistance with this, consider YourMechanic, as one of our mobile technicians can come to your home and replace your mass airflow sensor.

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