I know this sounds weird but here it goes. I have a 2004 Sable with the Duratec engine. Whenever it is cool and rainy when I first start the car the idle moves up and down. When I put my foot on the brake the idle sometimes hits a low point and it almost stalls. When the car almost stalls it raises the idle (and sometimes jerks) to correct itself. Could it be the IAC? This has been a good car and I want to keep it running good. Any help would be greatly appreciated!!