93 Cavalier RS fast idle

[SilentD]

ive searched all around the forums and couldnt find anybody else with this problem basically the car runs fine until it starts raining out.. then the idle picks up and it runs way too fast.. i could be going almost 30 MPH without even putting my foot on tha gas! just installed new spark plug wires and made sure they werent arching so that cant be the problem. there is a plug on the top right side im not sure what it is tho... when i unplug this the idle slows back to normal but then the engine eventually dies... weird that it runs perfect when its dry tho.... anyone else have this problem or have any idea what it could be? thanks in advance

[Helmuth48]

Hey mate.......not sure about the rain thing. But my first guess without more information ( CEL come on ??)

1st....I would say the the IAC valve is stuck open.
2nd....Bad wiring or connections with moisture getting inside. Spray all connections with WD40.
3rd... Stop driving the ute thru deep water and get a tinny !!!

Cheers !!!
JzJzz and the Man from Down Under....Time to head to the counter lunch and have a coldie!!