Re: 97 Taurus "Bucking" runs erratically

The vehicle speed sensor,(VSS). is a device sensor/mounted somewhere on the transmission that signals the transmission when to shift based on transmission shaft spindle speed. The transmission shaft spindle speed is also used to calculate the vehicle speed depending on which gear the transmission is in. It is driven by a geared wheel off the transmission, which sends a signal to the Power Control Module, PCM. When it does not work, due to a bad sensor or the wires broken, you get poor shifting or none at all, and of course no vehicle speed indicator on the speedometer. It is not a difficult repair. The hardest part for me was locating and reaching the sensor. On the 97 Taurus with a 3.0-V6 Vulcan, VSS is located on top of the Transmission, (passenger side.) in that space between the transmission and the exhaust manifold.(firewall side). It is near impossible to reach from inside the engine compartment without removing a lot of stuff, but not impossible. Go to the parts store, asked to see what a VSS looks like.( it has a distinct shape.) Once you have an idea what you are looking for, the job become a bit easier. Any competent shop with the right code reader, or scanner should be able to fix it. Have the shop run a diagnostic to get the error codes. The codes will narrow it down, if not pinpoint the exact problem.