must have forgot to plug this in...

as i was leak-testing my car earlier, i noticed a plug that wasn't plugged in...it plugged in to a spot right under the throttle body. but now my car doesn't idle at around 1,500 anymore....when i plugged it in, and started the car, rpm's jumped right to 2k and dropped to around 300 and stalled a second later lol...so i got out and adjusted the idle screw. got it to around 750 - 800 and holds it perfect now...that plug must have had something to do with the throttle but now i don't have to adjust my throttle cable....anyway, would having this thing unplugged cause any damage to anything or change performace being unplugged? i notice that when it was unplugged and i started the car, it would just go to around 1500 rpm's...like i said, now it jumps to around 2k and drops to idle...i think that's how it is suppose to be lol

Was it a large brown plug? The thing it plugs into under the TB is actually part of the TB correct? Sounds like it was your ISC connector. Without that the ECU has no way of controling idle speed (it does change timing, but that has a small effect on idle speed).

I could write another novel on how that screw should be adjusted, but I'll keep it short. That screw is used to bypass an amount of air around the TB that will allow the ISC to sit in the center of its travel idling in normal conditions, so it has maximum range in both directions (to raise/lower idle). Now, the hard part is doing that without the factory scan tool or DSMlink ;) If you don't have access to either of these, I Wouldnt bother worrying about it. You may just have to adjust it every now and again, and you may see some strange behavior with idle in unusual circumstances.

yeah i'm almost positive it was a large brown plug...sounds like what you are describing is correct...my car idles a hell of a lot better now since i plugged it in :)