1998 Ford Taurus Repair Question
Transmission slams up and down in gear at highway speeds and sometimes in lower speeds
You could have a throttle position sensor failure. If it is not that I would suggest taking it to a AutoZone or Advance Auto to see if any trouble codes come up. If they are solenoids, they are replaceable, if it is trorque converter solenoid, there may be torque converter and shift pack damage.
Make sure you take it to a transmission shop and not a reguklar repair shop as automatic tranmsissions require a good deal of special tools and a great deal of experience to work on.
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