I know this is of subject but need help wifes 1999 windstar 3.8 v6 I drove it today engine light came on took it yo auto zone showed tps throttle position sensor replaced it. now idle is high trany wont shift but if I disconnect the sensor runs fine idles good what all does this tps control and could it be a bad new one help

 

It could be a bad replacement sensor. I've had best luck with OEM or NAPA. The high idle could be caused by a vacuum leak. On the 3.8L engines the plenum to lower intake can be a source of the leak.

 

I;m not exactly familiar with that one, but some that are the 2 screw model need to have the screws loosened slightly and the sensor rotated on axis a bit to adjust out the correct idle. As we speak, we just finished doing this on my son's friends Camaro, but to get it right there is an exact measurement and you need a reader, his friend brought over the Snap-on diagnostic reader but you can get it going by ear after the vehicle is fully warmed up. Not sure if this will help, good luck.

 

The transmission needs to get info from the TPS as does the fuel injection system. Go to fordfuelinjection.com for info on how to test the TPS.
High idle and erratic or hard shifting can be caused by a bad TPS.

 

You can test the TPS with an ohm meter on the connecting terminals and do a full sweep of TPS. The readings should be smooth and progressive. Any sudden jumps or falling off of ohms indicates a bad TPS.