HELP: cant fix the CEL light

I recently bought a 4G37 5-speed eclipse. When I bought it the CEL light was on but I had no way of scanning it. Will after some research I was able to get the codes via a volt meter. The codes were the following:
Barometric Pressure
Engine Coolant temp sensor
Air Intake Temp
ISC-idle speed controller off

Now I went ahead and bought parts from the junk yard to replace the ‘bad’ or faulty components such as throttle-body, ECT sensor, and a MAS assembly. I still get the CEL codes even after the parts were installed and I disconnected the negative battery for a few minutes.
I then bought a datalogger and had a palm pilot to use to read and scan what the ecu was getting. I noticed the TPS % was stuck at 99.6%, both Coolant and Air intake temps were -77.x*F!!! something tells me either the ecu is bad somewhere on the circuit board or possibly a bad ground? It doesn’t make sense. Any help is greatly appreciated. Thanks!!

edit-by the way i also replaced the t-stat with a 180* and the coolant temp needle on the dash is just before the half-way point.

If it isn't a voltage issue, my bets are on ECU.

Same thing happened to my Oldsmobile. Said this and that were going bad and replaced each one, even though most checked out in near perfect shape. After a while, took the car in and the ECU was gone. Sounds like the same thing.

will heres the other part of the story i didnt add in. when i bought the car, it already had the cel light, but i didnt get it scanned yet. a few days later the capacitor leaked in the ecu and the car didnt fire up, only cranked. i then went and bought a reman ecu that alreayd had the 3 caps swapped with higher temp caps but it looked like the person who did the soldering used a bit too much of solder as it was a messy job they did. that was when i scanned the car and pulled the CEL codes.

i also bought a haynes manual but i only was able to test the voltage off the MAS sensor wiring harness. i tested using the volt meter and probed the port 1 and it checked out with what the manual said, IIRC ~12v, then tested the port 2 off the MAS sensor wiring harness and it pulled ~4-5v just like the manual said.

DAVID-B, i tried reading what you wrote, but im having a hard time understanding what you meant. sorry, didnt mean to offend u if i did.

-ECU threw codes for different senors
-Replaced those sensors
-More codes from ECU
-Was bad ECU

Not offended, didn't think it was that hard to understand to begin with.

ok, that makes more sense, thanks david-b. im in the process of getting another ecu, dunno if its gonna be a waste of money, but its worht a shot i suppose...

Ok I have to agree with everyone on here. the question i have for you is have you ever soldered anything like that before? You can clean them up and see if any joints tuched in the wrong area or if the traces are bad. There are ways to fix it but like everyone else said the ecu is probably the problem. There is one company I would trust to buy from and thats motoguys garage.com you can google it for there site address.

IIRC, all of those sensors are 5v sensors. But you say that the 5v at at least one of them was good? Check the manual and see if they all share the same sensor ground or something. Seems odd that a whole bank of 5v sensors woudl shit the bed at the same time. The 5v will come from inside the ECU.