I have found a company on eBay that will go through the ECU and make whatever repairs are necessary and give a lifetime warranty (not sure how that's possible on electronics) and the price is $98. I looked and the number of transactions for the company is over 700 and their feedback score is 100%. They also indicated they would diagnose whatever concerns and if it does not look like your ECU is repairable within reason, they would refund the full purchase price.
Here's the dilemma. At some time during this car's life, it had an ECU issue which resulted in its replacement. Had the person who swapped the ECU not installed an A9L, I may never have known it was replaced. Secondly, the replacement had to occur after bumper-to-bumper warranty expired. Otherwise, the dealer would have installed a replacement A9P. The big question is this: If I have my ECU repaired and reinstall it, is there any likelihood that the repaired ECU will fail similar to this one? In other words, is there something else lurking that could cause the ECU to fail again? Remember, even with this failed ECU, everything works,,,even if it is in limp mode (and runs like crazy). The only real objection is the CEL...and the bulb can be (difficultly) removed.
You are much smarter than me on the electronics of a Foxbody. What would you do?