I am getting a 2-2-3 code on my 1990 740 GLE. The idle air valve has only two pins, how can it send an error message when it has only the ability to open or close? I am getting idle surge on start up, from 400 to 1500 RPM, making it undriveable when this happens. It will suddenly return to normal then go back to surge, cold or warm. I have cleaned throttle body, replaced most vacuum hoses and reset the TPS, cleaned and checked Mass air flow. It may go 3 or so days then die again, anyone got some input on this one? I have left the Idle Air valve disconnected, and blocked off the two vacuum connections for it resulting in a lower than normal idle.