NB2 alternator and idle issues

[HarryB]

As you might have already noted from the title, my quest to eliminate my idle issues is continuing. Now the car idles high (around 1000rpm) but not all the time. And while everything points to a clogged IACV, I did a "test" today which confused me. When idling and with the windows up, I hit the window switch in the "up" direction, at both sides simultaneously. Increased electrical load caused idle to go south (700ish) and after I release the switch it will idle steadily at around 800 most of the time. Sometimes it requires 2-3 tries until it does it; leading to me wondering if it could be alternator related.

[NCGreasemonkey]

My thought would be your first idea. IAC. It probably has carbon build-up on the stem and the return spring cannot pull back through the smuts. When you load the electrical side the signal to the IAC drops lower and the spring, combined with engine vacuum, can shut it more.

If you don't want to pull the IAC try hitting the opening for it with some thottle body or carb cleaner in short burst with it running. Yes you might have some running issues if you have the MAF still in the loop. But you can disconnect the battery afterwards and clear everything then let it relearn.

HTH, :cheers:
Rick