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Q: Do I need a crankshaft position sensor

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Car runs fine at traffic lights it idles a little rough,,had tune up ,mass airflow sensor replaced

My car has 170000 miles.
My car has an automatic transmission.

A: Typically a bad crank position sensor will ...

Typically a bad crank position sensor will prevent your vehicle from starting. Your rough idle could be due to a vacuum leak or possibly a dirty injector, or maybe even an idle air control valve or throttle body that needs cleaning. If you notice the problem getting worse, I would recommend having a certified technician, like one from YourMechanic, come to your home or office to diagnose your rough idle and make the necessary adjustments or repairs.

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