02 tacoma ecu failure

Truck history: 4cyl 2.7l 4x4 extracab,manual. From Maine.
2010 Toyota recall, replaced frame, leaf springs, hard break lines and fuel line.
2011 I bought her with 88k for $8,500. Stoked!
Very little matnience required, ran great. Virtualy no modifications until last winter. This spring my ecu died. Here's a list of the electricle components I installed.
I wired up a pair of KC fog lights using a KC wiring harness straight to the batery not wired into the headlights. They work great, no issues.
My in inverter is hard wired to the batery using an inline fuse on the positive run 12" from the batery. The inverter is in the bed of the truck. It has been damp and the USB port has stopped working last fall sometime (might be my culprit).
I have a xrc 9.5 winch I installed. It is wired correctly and works properly. The only issue it has is the silinoid box was cracked when I got it, occasionally when winching in, it will flip in to reverse, to stop it I have to push the switch in to reverse then forward again. I'm in the process of getting new parts from smitybilt.(this to could be my culprit)
My ARB air compressor is mounted on the pasenger side under the hood, where the ac would be. It is wired correctly and incorporates it's own inline fuse. It works with out issue.
The only other mods I did the could effect the electrical system:
Third reverse light wired into the factory reverse wiring, works fine.
USB port hard wired into ash try light. I cut the bulb out and emoved ash trey, now there is a 4 port USB charger there. It has a switch built in and I keep it off unless I'm using it because it has constant power.
I have a head unit that I installed in 2011 and has had no issues.
My rock sliders are welded to the frame, we disconnected to batery and properly grounded before welding. I am keeping this as a posability as to what killed my ecu but the truck had no issues imidiatly after the instal.
The trailer wiring was not working properly and I don't tow trailers so I removed it back to the factory wiring
One of the licence plate lights won't work and never has since ive owned the truck. I assume both these problems are from the new frame install and never caused any problems.
So now the story starts.
Blown 20amp EFI fuse while driveing (2nd gear, 20mph, smooth dirt road, shallow creek crossings 20 mins before, bottom of truck had been wet from splash but it was hot and dry out so when that fuse blew the truck should have been dry) in moab. I replaced it and on I went thinking either it was either just it's time or my fuel pump is about to go.
A month plus goes by and the EFI fuse blowes again, I replaced it,
drove 500 yrds and it blew again.
After 8-10 fuse's and getting out of the woods the truck started running on two cylinders. Up to this point the truck ran great until it blew the EFI fuse and would stop pumping fuel and stop dead. Now running on two cylinders it would not blow the fuse. I got towed to my Toyota tec and he found cylinders 1&2 where fouled and 3&4 had no injector pulse. He then traced it back to the ECM/ECU.
He also checked all leads and grounds, all look good. We got a used ecu for $180, put new spark plugs in and she fired right up. Ran fine for about 100 miles. I noticed a small amount of power loss but normal operations where all there.
At 10mph I went threw a puddle on a dirt road. It was probably the 8th puddle I'd gone threw in a mile stretch. I came out the far side of the puddle with no throttle response. I put in the clutch and she died. I tried starting it a few times, she'd start but not well and wouldn't idle. I started smelling burnt plastic so I aired her out and left her for the night (way out in the woods)..
EFI fuse had not been burnt.
After getting her to the shop again, we replaced all four injectors with rebuilt OEM injectors thinking they where not drawing the correct amount of currant. This was my tecs idea, we now think it was not neccicary bot it was only $120 in parts so oh well.
I sent my ecu in to SIA electronics who i found on ebay and they said they could rebuild my ecu for $175. We plugged in the rebuilt ecu and it was not sending injector pulse for 3&4 still, as if nothing had been done to it. I'm not sure what to think about that, maybe it's a scam and the did nothing to it or maybe they didn't do a good repair job. They said send it in and they will take a look at it. I found another used one so I ordered it due to the fact that I lost faith in the rebuilt one.
Out of curiousity i opened the fisrt used ecu, an area of the board was burnt.
My inverter got left on after the tow,(power button must have been hit when thowing a stap in the bed) after two weeks of being on it drained my battery. The inverters low power alarm sounded so I disconnected it at the bed, leaving the negative end just sitting on my rubber bed mat. We put it on charge, it wouldn't charge above 35%. My tec disconnected all of my accessorys and put it back on charge, now it charged up to 85%. I think that is because the inverters wiring was left open, tricking the charger into thinking goes there was more batery to charge. My tec on the other hand thinks there is a voltage spike coming out of one or more of my accessory. His plan is to disconnect everything I added to the system and plug in my second used ecu and the truck should run. He thinks I should be all set then.
So this is where I stand,
-Why did it stop blowing the EFI fuse and start blowing computers?
-If a voltage spike is coming out of my acceserys why are there inline fuse's not blowing? Do they need fues's on the negative runs aswell?
-there's no way to know if the problem is fixed, just hoping it doesn't fail again...
-if I disconnect my accessory's and the new ecu doesnt fail (say in 1000 miles) than how can I be sure they arwill not going to fry my system again when reconnected.
- why would problems start long after all accessory where installed, tested and used?

I plan on a dual batery system from Columbia overland using an IBS buthe I'm concerned I'll fry it if I don't find the root problem. It would be a good way to monitor my batery and separate the acceserys from the factory system.

I mentioned to truck getting wet because the idea of a ground not being connected to the new frame is an idea or a shorted wire somewhere getting wet. Everything looks good though.
Electrial therory is a bit over my head but my tec is certified toyota, taught toyota tecs for many years and has been in contact with other tecs. It just doesn't make sence. My tec is convinced it's a voltage spike. I'm at a loss and missing the he'll out of my truck.
Can anybody help?

 

160k miles now
I sent in my factory ecu for rebuild
Sorry about the typos.