[ethangsmith]

I've been having some issues with the automatic in my 99 wanting to shift way too early out of first gear and then slipping slowly into second and some other strange drivability issues so I got a much lower mileage PCM out of the junkyard. It is the EXACT same calibration and everything. I popped it in and drove around and the transmission shifting is better and so is the other weird issues I had, but not totally solved yet. Anyway, I had read several places that the PCM's are all programmed to the exact car they came in. Do they store the VIN number in them or something to identify them? I put my scan tool on it and I couldn't get it to spit out a VIN or anything else that would identify it as being swapped out of a different car. So are these things really mated to the cars from Ford or is that a rumor?

 

[madmatt2024]

I say that's a rumor. Some cars have PCM's that have the VIN code for the car they left the factory in. Chryslers are known for this but as far as I know the Escorts didn't have such a thing.

The issue you are experiencing could be you TPS or VSS on its way out.

 

[ethangsmith]

TPS was just replaced. VSS seems fine. No speedometer issues. I popped all the wire connections apart and cleaned and greased them. I also had the tranny flushed.

 

[Rex]

TPS was just replaced. VSS seems fine. No speedometer issues. I popped all the wire connections apart and cleaned and greased them. I also had the tranny flushed.

And that's probably why it seems better. PCM is either working or broken and they are not car specific, but they are configuration specific like auto, fed emissions, manual trans, etc.

 

[ethangsmith]

It did improve the overall running of the car significantly when I replaced all the sensors, but the most improvement thus far is when I swapped the PCM last night. On my travels to and from work, the car ran smoother and with much more power. The transmission still gives the occasional slip on the 1-2 shift, but it's not as pronounced and long.