I am trying hard to get my 90 wagon with a 2.2 and 5 speed to pass smog in California. I have already changed the IAC and the ECU up under the dash. I guess the only other thing could be the wiring. I have done the test at the IAC harness and it is giving me a reading of the battery voltage of 13ish volts before start, 12ish volts after start, then drops slightly and a minute later goes to 0 volts. It is my understanding that it is supposed to go to 1 volt, then 10 volts after one minute. The car seems to run fine regardless of this problem but I need the Check engine light to work properly to get it to pass smog. Any help would be appreciated. My next step will be to jumper directly from the ECU to the IAC harness to see if the stray voltage will go away.