If the engine is intermitently stalling, and runs fairly well I would suspect the ingition pickup coil and TFI module (ignition moduel) are faulty. To correctly diagnose this condition the waveform and frequency of the pickup coil needs to be checked with a lab scope. The inputs need to be checked to the TFI module, the wiring from the computer to the pickup and module also need to be checked, and the power and grounds to the computer, as well as the computer itself may be bad. Although from my experience if the engine does not want to start it is more likely the TFI, pickup, or computer. But if it starts and runs, but intermittenly stalls, it's usually the pickup or TFI module. The TFI module is located on the side of the distributor and the pickup is inside the distributor and requires disasembling of the distributor to access. You may choose to replace the TFI module yourself since it is fairly inexpensive and easily installed, you'll need 5.5 mm socket 1/4" drive to remove. There's always that possibility that it can be any of the above items causing the fault, but even most repair facilities cann't correctly diagnose this problem because of it's intermitancy, and often recommend replacing the TFI and pickup first.Also, try wiggling the wires at the distributor while the engine is running and see if the engine will stumble or stall, this is recomended on all earnlier Fords, due to the wiring breaking internally. One last item, next to the distributor is a connector with a cap in it, make sure the cap is on. This is the timming connector and and interupts the PIP signal for base timming adjustment, if the cap is missing the symptoms will be similar.
-Rip
__________________
Please click on "ACCEPT" if I was helpful-or if you still need assistance just reply, before leaving any feedback thanks 
