My gf just got a 91 NA and in the last two days it has developed an idle problem. I did already search for idle problems but nothing that matched my symptoms very well.

The car starts fine. Sometimes it runs fine. Other times it starts hover around 1k then dies. I adjusted the idle (once it was running) up to a little over 1k and it's fine until the air is turned on. If you slowly turn the fan up the idle drops to about 900. But if it's turned on normally it just dies. Also rolling down a window and holding the button after it's down affects the idle and has made it die on occasion.

I looked for shorts in the wires behind the alternator and read a post about the ECU.

Thanks in advance for any help.

 

Sounds like your BAC Valve to me(Bypass air control). It is supposed to help your car maintain an idle when you turn on AC, or anything electrical.