OK, a couple of other things to check.
The computer uses it's own ECT(engine coolant temp) sensor, it is not connected to dash board temp gauge.
ECT sensor is a 2 wire sensor.
Dash gauge uses a 1 wire sender.
The 2 wire ECT sensor is easy to test with OHM meter, look here:
http://oldfuelinjection.com/?p=28
When computer reads ECT sensor and "sees" cold engine it will run engine rich with advanced timing and high idle, this is "choke mode" for EFI systems.
As the ECT sensor warms up the computer "sees" this and leans out mixture and starts to lower idle.
If ECT sensor or wiring is bad then computer "sees" cold engine and runs rich all the time.
ECT sensors rarely fail, not never but rarely
Next, if possible borrow or rent a fuel pressure tester.
Fuel pressure should be between 30-35psi, engine off or engine on.
The computer has no way to "see" fuel pressure, it assumes 30-35psi.
If pressure was 40-50psi then injectors are open too long, too much fuel is going in causing rich condition.
This could be a Fuel Pressure Regulator(FPR) issue, FPR is on the fuel rail it has a vacuum line attached, remove vacuum line and check if there is fuel inside line or it smell like gas.
If so replace FRP.
Also check the whole vacuum line for holes or cracks, it must be a good vacuum or FPR can't work.
If no smell or gas in vacuum line then watch fuel pressure when idling, remove FPRs vacuum line and fuel pressure should go up, reattach and fuel pressure should drop to 30-35psi.
If removing and reattaching FPRs vacuum makes no difference, replace FPR
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