First thing I would do is make sure all your grounds are clean and good from the battery to the block and block to the frame etc..When you get out of range codes it usually means the EEC is reading improper voltage. Take your salt n pepper shakers apart and clean the terminals although they may need all of the wires repinned on both halves and have the harness removed and bench tested........Still working through my rough idle on both cold (really rough) and warm (a little rough with random stalls). I did set my base idle and a vacuum leak along the way while working through the checklists on the site but now I am kinda stuck. Now, when cold, the car starts and dies once. On second try it starts, idles at 1200 RPM for about 30 sec, then slows down to about 750 RPM and then idles very poorly and I struggle to keep it running. After about 2 mins of rough idle, it smooths out at about 750 RPMs but randomly sputters, then smooths out again. Eventually it will just sputter and stall. If I pull the SPOUT it idles smoothly and does not sputter or stall. I replaced a few sensors (IAB, ECT, TPS and reset base idle with SPOUT removed) because of the error codes I was getting previously but now I really think my problem is electrical. Here's why. From the beginning of my issue, I have been getting the KOEO codes 15 and 96. I replaced both fuel pump relays and have good voltage at the pump, relays, ECU. I gave up on code 96 for a while. I dumped the computer memory and took the battery out of my code reader to dump that memory as well. Now, the KOER I get codes 82 (key on engine off code), 22 (BAP sensor out of range), 61 (key on engine off code). Car was warmed up when test was run. Disconnected the battery for 30 mins and ran the KOER test again and this time got 82, 12, 22. I also noticed during my last year of troubleshooting with the checklists and code reader I have never received code 11 and per the checklist if I never get 11 that means I have some sort of electrical issue. The only thing I have done with the car on the electrical side is upgraded the alternator to 3G and I did install another ground wire, as recommended by the checklist. In the past I have also received engine running codes that make no sense, like 62 and 2. Lastly, when the KOER test starts in the very beginning I expected to see "8" to show it was an 8 cylinder, but it always shows "0".
So, I apologize for the long post but I now am looking for some suggestions on how to move forward to see what electrical issues I could be having. Car has been sitting in the garage since April of 2021 and its killing me slowly. Car ran great for about 5K miles before this stuff started happening.
93 LX Conv, original motor (32K miles), original AOD replaced with TREMEC TKO600, boat load of suspension, brake and drive train upgrades.