Here's what I have found out so far about the 3 major drive-ability issues:

Almost everyone has experienced off-throttle stalling, a pretty big 2500 RPM flat spot, and severe backfiring. Ford recommends their part number M-4209ADPT-A, which they refer to as a Speed Dial Adapter. Its original function is to adjust for rear gear or tire size changes, but in our application it is just an on-off switch that tells the ECU when the car is moving. FFR has known about this for quite a while but for some reason neglected to share the info. Several of us have gotten the heads-up from Ford independently. The members who have installed the device claim it fixes the stalling problem and the dead spot problem.

Installing the adapter requires breaking in to the ECU harness at the smallest of the 3 plugs. Two wires have to be added and the necessary pins do not come with the adapter. Ford will send you some as long as their supply holds out, but I'm looking for more (TYCO/AMP). The instructions show the plug having a white face, but in my harness it is red. The locations of the used/empty pin positions jive with the schematic, but the wire colors do not. In any case, here is the link for the install instructions for the adapter as well as a set of alternate instructions found on another forum.

http://www.factoryfive.com/wp-conten...tructions1.pdf

Additional link to be added

There is no need to calibrate the adapter since the unit only acts as an indicator of vehicle movement, it does not feed speed data to the ECU. The leads from the trans mounted speed sensor are polarity sensitive, so a trial and error might be required. I am NOT attempting to drive both the speedometer and adapter with one sender, although I have been told it can be done. I am converting my Speedhut speedo to GPS.