Garage Cabinets, Garage Storage, and Garage Organization

I have a 98 Taurus station wagon that is getting the code P0500 from the check engine light. That code calls for replacing the vehicle speed sensor. I first bought one from the parts store, installed it and the erratic shifting continued.

We pulled out the new sensor and put the old one back in and the car drove great for about 4 days until the check engine light came on again with the same P0500 code.This time I replaced the old one with a dealer bought sensor, still no luck.

Someone suggested that the problem might be the pcm or turbine speed sensor, so I replaced the tss with a new one and picked up a pcm from the junk yard and tried to install that. The new pcm gave us more errors because it wasn't the same as the original pcm.

Replaced the old pcm and now I am back to the original P0500 code, but after replacing the speed with 3 new sensors I'm pretty sure that the problem is not the speed sensor.

Any suggestions would be greatly appreciated.