I have a 1989 volvo 780 and have been doing research about adjusting the air mass meter set screw. Different websites tell me different things to do and I need some clarity on the issue. I went to the air mass meter and set the 380 ohms as mentioned in some books, but the calibration procedure baffles me a bit. On my fendor well I have two open pigtail connectors--the driver side has one with two wires (pink and red/yellow), the passenger side has an open double pigtail with a green/white and red/white wire. Which one of these pigtails is for testing purposes. Some of the things I have read talk about grounding the red/white to di wire to disable the IAC(idle control valve...coudn't I just dissconnect the harness to it, I don't like trying to short out things on volvos) andthen turning the thumbscrew to idle at about 725 rpm. Then it talks about putting a special connector on the white/green wire that has an led..when the led blinks at equal intervals..its supposed to be set. Then I read things about testing the o2 sensor at .3-.7 volts..some say get if from the green wire at the boot connector at the harness where the o2 sensor connects...some say disconnect it and read the voltage and some say get it from the green/white wire I was just talking about..so can you see why I am confused and frustated...SOS..does anyone really know the proper procedure...thanks...Leo