CODE #24 ONLY - ECU or MAF Circuit Issue?

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Hey guys, here's the details below. This one has stumped many shops and I'm finally honing in. I would like to avoid building and installing a stand-alone harness for both the TPS and MAF circuits and feel that this testing proves the circuit in the ECU itself is shot. All parameters are reading spec values when tested - without diving deep into an oscilloscope - and to me this would point to a faulty circuit in the ECU itself. Just wanted to hear other opinions before I place the order and if anyone has one that's good with numbers 89661-50102 I would love to buy it. It's pretty rare unfortunately. Thanks for the adcive

-Vehicle - 77 Toyota with 1uzfe from a 92 Celsior (ls400 in US) JDM motor mated to a 5 speed, ECU is independently powered and de-loomed
-Condition - for about 2 years I've had an issue with my ECU throwing code 24. It runs fine but without turning the idle up to 1000rpm (via clocking the TPS) it dies when coming off gear to a stop every time. When turned up it runs fine but jerks when coming on and off the gas due to a clocked and non stock setting TPS.
-Testing details:
- MAF pin 1 to pin 2 to test THA to E2 circuit = 2.4V and 2.9V (I have 2 MAFs) at room temp of = PASS per spec
-MAF pin 5 harness to battery ground = PASS continuity
-MAF Pin 4 key in ON position without vehicle on = PASS 5V per spec
-MAF Pin 4 to TPS pin 3 = PASS continuity
-MAF pin 1 (E2) and pin 2 (THA) = PASS continuity to ECU
-With E2 and THA back pinned on the ECU side plug I measured Volts between E2 and THA with key ON = PASS 2.7V constant