Speedometer goes up& down,cuts off at low idle after car reaches tempeture,no check engine codes...could the speed sensor cause this
My car has 130000 miles.
My car has an automatic transmission.
There are several reasons why this can happen and with limited information it can be difficult to narrow down the search. Some of the more common things that I have seen that can duplicate these symptoms are dirty throttle bodies, dirty/faulty idle air control motors, and vacuum leaks.
I would recommend enlisting the assistance of one of a certified technician. They will have the tools and experience needed to determine exactly why your vehicle is cutting off and experiencing a low idle. They will also be able to address the erratic speedometer. They can also assist you with making the repairs necessary to get your Impala running and idling smooth again.
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