I own a 1996, Land Cruiser VX 80 series 4 wheel drive. The car battles to remain at 750rpm when warm. It has half its power up to 3000rpm. Its possible the ECU is faulty or the sensors(water, O2 etc.) are faulty. I unplugged what I though was the ECU and suddenly all the power returned, however after a few minutes it returned to its previous state. Can anyone tell me where the ECU is located and how to test if I need a new one. What would be symptoms of a bad one!

I have had issues with my '94 L/C for over 6 months now and I have ran out of money trying to diagnose the problem. The vehicle starts up cold and works perfectly, but when it warms up, it seems to miss and shifts VERY erratically. I have had it in 5 different shops, starting off with a local Toyota dealership, who replaced the fuel regulator. When it didn't fix the issue, they wanted to replace something else. I wasn't in the frame of mind or the financial shape to keep letting them replace $500 items and think nothing about it(I'm a full-time school student). The second place, who was an import specialist, diagnosed it as a bad ECU. They sent my ECU off to a repair shop for a rebuild at a engine computer repair specialist place in Houston, TX. The ECU rebuild shop claims they repaired the problems in the ECU. After we got it back and tried it, it had the same problem once it was reinstalled. The diagnosis code was a bad ECU still. We sent it back to the rebuild shop, and they said it was repaired wholly. He then replaced the Transmission Control Unit with a factory unit. That shop said he was at his wits end. The next shop(#3), which was a Toyota/Lexus repair shop, the Toyota Master Mechanic diagnosed the ECU also. He referred me to a Transmission specialist, who replaced the gear indicator sensor. He said he had no idea what to do next. The next place was a automotive electronics specialist had my vehicle for 5 working days and derived that it was a faulty Speed Control Module, which was then disconnected. I drove my vehicle home thinking my problems were over. I got home and nothing was different than when my woes started. I LOVE my L/C, but I am out of money and stressed out.