Unsolvable Issue Please Help

Maui2Thicc

Hi to everyone reading and thank you for your time.
I made the transition from a 2017 86 to a z34 for almost a year now.
A 2009 Base to be specific.

Info on the car:
Automatic Originally
Drives fine atm
93k on odometer
Last work done on car was Bank 2 Sensor 1 replacement
Service Engine Light On (P0850)

YES, you read that right. Originally automatic. I am the 4th owner and one of them did a auto to manual transmission swap. Something to remember for later in the post.

Where it begins..
So im driving and suddenly throttle cuts off. Rpms are limited to about 2.5k.
Car did not shut off! I then rolled into a parking lot, turned her off and on, no throttle response. Get her towed to the shop they say it was caused by one of the Variable Timing Solenoids failing. Cool, get it replaced and everything is fine....for a month and a half or so. Then same thing happens, take her back to the shop. This time it was the second VT Solenoid. Cool, get it replaced and alls good. Right? Nope.
A few months later same thing happens This time they cant figure it out. No thrown code. They traced the problem to a relay and replaced it. That same day it happens again at night.
Im stumped, the shop is stumped and i refuse to go to nissan due to pricing and experience with dealer mechs.
Then a code pops up. A P0850. I buy the Park Postion switch and when they are about to install it... There is no connector. Upon further inspection, they come to find out that the car was manual swapped. Im shook because I never expected that. So I call Nissan give them my VIN and BAM. Automatic comes up for transmission. So I go to another shop for a second opinion and they say the same thing. Also they say it was done correctly.
But why am I bringing all this up about the transmission? If it was done correctly.
Except the wiring and ecu.
They kept the stock ecu, which makes it an automatic base ecu. Which is also why the car is throwing the P0850. Some other red flags are that the reverse lights dont turn on when in reverse gear.

Now How does this tie into my limp mode/throttle loss problem?
So When it happened again i decided to completely disconnect the battery (positive and negative terminals) to reset the ecu.
I then did all the relearn procedures for Throttle and pedal.
BAM, Shes back to normal and driving.
So now reseting the ecu is my only fix but it started happening every FEW miles. So i let her sit for 2 weeks straight. I started driving her since last friday, 15th of November. There are no issues so far and she has been driving fine even under light stress. Now im shot and am focusing on the ecu as the main culprit. Friday i will be ordering a same model year ecu from a base manual and will be trying my luck. I believe some wiring still needs to be done. But I want ANY feedback and questions. Please.

MY Questions are:
-If the code suddenly popped up and the sensor was never connected to anything then shouldnt the code have been present even during the test drive and purchase of the car? as well as through out the whole time of ownership?
-Did the ecu have to be tampered with in order for the car to even accept the manual tranni?
-If ecu was tampered with could the ecu have just gone bad over time since it was first swapped?
-Is it even the ecu?

Current issues with car other than the ecu problem are that the ac compressor needs to be swapped, the power steering pump and sensor as well. I will be ordering those soon as after the ecu.

Sorry for the long read and thank you again for your time.