I've gone through the service manual troubleshooting and this is what I've got so far.

Testing over voltage protection relay
-Terminal 1 of ECU connector has battery voltage. OK
End of Test.

Testing Coolant Temperature Sensor
-Coolant temperature sensor values are correct. OK
-Read current value going to EHA. NOT OK
-Test resistance of EHA. OK
-Test continuity from coolant temperature sensor to ECU. OK
-Test continuity from EHA to ECU. OK
End of Test.

Testing Acceleration Enrichment and Airflow Position Sensor
-Read EHA current value at idle and under quick acceleration. NOT OK
-Read voltage between terminals 1 and 2 and between terminals 1 and 3. NOT OK
-Read voltage while deflecting airflow plate. NOT OK
-Test wires between ECU and airflow position sensor. OK
-Test RPM signal. (didn't get around to this)
-Test continuity between EHA and ECU. OK
End of Test

Testing Throttle Valve Switch
-Check resistance of switch at idle and full throttle. OK
End of Test

Primary Fuel Pressure: 5.8 bar OK
Lower chamber pressure at idle at 80°C: ?
Lower chamber pressure at idle at 20°C: ?
Lower chamber pressure at acceleration at 20°C: ?

Notes:
-My fuel pressure test kit is not able to reach the lower chamber port.
-I am not getting 5 volts to the airflow position sensor, but signal and ground are present and working.